Seedling needle punch forming device and punching process thereof

Abstract

The invention belongs to the technical field of stamping dies, and particularly relates to a seedling needle stamping forming device and a stamping process thereof.The seedling needle stamping forming device comprises an upper die, a lower die, a first guide column, a multi-stage buffer assembly and a one-way unloading assembly. The upper mold is provided with an upper mold plate with a mold core, the lower mold is provided with a first cavity, and a lower mold plate with a mold cavity is movably arranged in the first cavity; the first guide column is matched with a first guide cylinder of the lower die, and a second cavity is formed in the guide cylinder. The multi-stage buffering assembly achieves pre-buffering and secondary buffering by compressing gas in the two cavities, the one-way unloading assembly only allows gas in the second cavity to flow into the first cavity in a one-way mode, and the size of the first cavity is larger. Through graded buffering and one-way unloading of the two cavities, the peak value of buffering counter-acting force is reduced, impact damage to the die is reduced, guiding and forming collaboration is improved, the seedling needle forming precision is guaranteed, the service life of the die is prolonged, and continuous and efficient punching is adapted.

Description

Technical Field

[0001] The invention belongs to the technical field of stamping dies, and in particular relates to a rice seedling needle stamping forming device and a stamping process thereof. Background Art

[0002] The seedling needle is the core component of the rice transplanter, which mainly relies on stamping. The stamping mold usually includes an upper mold with a core and a lower mold with a cavity. The upper mold is driven downward by a driving device (such as a press), and the blank is stamped by using the cooperation of the core and the cavity.

[0003] However, in actual applications, traditional stamping dies mostly adopt traditional rigid stamping structures, which are subject to large impact loads. Even if a buffer device is installed, the service life of the die will be easily affected due to the large reaction force accumulated after buffering. Summary of the Invention

[0004] The purpose of the present invention is to provide a rice seedling needle stamping forming device and its stamping process in response to the above-mentioned technical problems, which achieves multiple buffering and directional unloading, avoids deformation and cracking of the mold or loosening of fasteners, and extends the service life.

[0005] In view of this, the present invention provides a rice seedling needle punching and forming device, comprising: The upper mold is provided with an upper template, and a core for forming the rice seedling needles is provided on the upper template; The lower mold is provided with a first cavity, and a lower template is movably provided in the first cavity, and a cavity is provided on the lower template to match the core and be used for forming the rice seedlings; The first guide post is provided on the upper mold, and the lower mold is provided with a first guide cylinder adapted to the first guide post, and a second cavity is formed in the first guide cylinder; A multi-stage buffer assembly includes a pre-buffer unit and a secondary buffer unit, wherein the pre-buffer unit is disposed in the second chamber and performs pre-buffering between the upper mold and the lower mold by compressing the gas in the second chamber, while the secondary buffer unit is disposed in the first chamber and performs secondary buffering between the upper mold and the lower mold by compressing the gas in the first chamber; a one-way unloading assembly connecting the first chamber and the second chamber and allowing only one-way flow of gas from the second chamber into the first chamber, so as to transfer the compressive load of the second chamber to the first chamber; The volume of the first chamber is larger than that of the second chamber, so as to reduce the peak value of the buffering reaction force through a larger buffer space.

[0006] In the above technical solution, further, the pre-buffer unit includes: The first piston is slidably connected to the inner wall of the second chamber and has an embedding hole at the top thereof adapted to fit the first guide post; a first spring, installed in the second chamber, with two ends respectively abutting against the first piston and the bottom wall of the second chamber; The lower mold is provided with an air inlet connected to the second cavity, and a first one-way valve is provided at the air inlet.

[0007] In the above technical solution, further: The static friction resistance between the first guide column surface and the inner wall of the embedded hole is greater than the static friction resistance between the first piston surface and the inner wall of the second chamber, and a first annular protrusion is provided at the top of the first guide cylinder for limiting the first piston from leaving the second chamber.

[0008] In the above technical solution, further: The one-way unloading assembly includes a communication channel connecting the first chamber and the second chamber, and a second one-way valve is installed in the communication channel; The second one-way valve is used to conduct the second chamber to the first chamber and to block the reverse direction.

[0009] In the above technical solution, further, the secondary buffer unit includes: The second piston is mounted on a side of the lower template close to the first chamber and is slidably connected to the inner wall of the first chamber; The second spring is installed in the first chamber, and two ends of the second spring are respectively in contact with the second piston and the bottom wall of the first chamber.

[0010] In the above technical solution, further comprising: The ejector assembly is installed in the lower template and includes an ejector plate, a drive unit and an exhaust unit, and a vent hole is opened through the second piston and the lower template; After the core releases the restriction on the ejector plate, the driving unit provides a driving force through the air vent by the pressure difference between the inside and outside of the first chamber to push the ejector plate, and an annular groove is provided on the inner wall of the air vent and a second annular protrusion is provided on the surface of the ejector column for sliding along the annular groove; The exhaust unit is used to discharge the compressed gas in the first chamber after a single stamping process.

[0011] In the above technical solution, further; The driving unit includes a push rod slidably connected to the vent hole and a sealing ring installed between the ejector plate and the bottom wall of the cavity, and the sealing ring is used to seal one end of the vent hole; The vent hole is a stepped hole, and the axial dimension of the stepped hole is larger than the axial dimension of the top column.

[0012] In the above technical solution, further: The exhaust unit includes a countersunk hole axially opened in the top column and an exhaust hole opened on the inner wall of the countersunk hole; The exhaust hole is located on the side of the top column close to the top material plate.

[0013] In the above technical solution, further comprising: The second guide post is mounted on the lower template, and the lower mold is provided with a guide hole corresponding to the second guide post; The second guide cylinder is installed in the guide hole and is matched with the second guide column.

[0014] The present invention provides a stamping process of a seedling needle stamping forming device, comprising the following steps: S1: Place the rice seedling blank on the cavity and drive the upper mold to move it close to the lower mold for mold closing; S2: After the first guide column enters the first guide cylinder, the pre-buffer unit is pre-triggered and pre-buffered. During the pre-buffering process, the gas in the second chamber is compressed and gradually guided to the first chamber. S3: When the core on the upper template contacts the seedling needle blank and pushes the ejector plate to squeeze the sealing ring, the first chamber forms a sealed space; S4: The upper template pushes the lower template downward and compresses the first chamber. At the same time, the gas in the second chamber is continuously squeezed into the first chamber. S5: When the gas pressure in the second chamber is lower than the gas pressure in the first chamber, the second one-way valve is closed, and the first chamber is continuously compressed until the rice seedlings are formed; S6: The upper mold moves upward to move it away from the lower mold for mold opening; S7: The first guide column drives the first piston to return to its original position and opens the first one-way valve to inhale air; S8: The core releases the contact between the seedling needles and the ejector plate, and the compressed gas in the first chamber pushes the ejector column through the air vent to lift the ejector plate and the finished seedling needles; S9: The compressed gas in the first chamber is discharged through the exhaust hole, and steps S1 to S9 are repeated.

[0015] The beneficial effects of the present invention are: 1. Pre-buffering is performed through the first guide column, and then secondary buffering is performed between the upper template with the core and the lower template with the cavity through the secondary buffer unit to ensure multiple buffering effects and improve mold clamping stability.

[0016] 2. The gas in the second chamber used for the first guide column buffer is guided into the first chamber through the one-way unloading component to reduce the pressure peak in the second chamber, avoid overloading of the pre-buffer unit, protect the structural integrity of the pre-buffer unit, extend its service life, and avoid deformation of the first guide column and the mold or loosening of fasteners.

[0017] 3. Through the second one-way valve, the gas in the second chamber is only allowed to flow into the first chamber in one direction, and the volume of the first chamber is larger, and the exhaust speed of the exhaust unit is lower than the speed of the gas in the second chamber flowing to the first chamber. Therefore, the gas in the second chamber can gradually and steadily fill the first chamber, so that the first chamber slowly rises from normal pressure, so that the pressure difference between the two chambers is always within a controllable range, avoiding the impact caused by the sudden influx of high-pressure gas, and improving the stability of the overall buffer system.

[0018] 4. The gas is transferred from the second chamber to the first chamber, so that when the core and the blank are in contact, the first chamber has a certain pressure, thereby avoiding a sudden rise in pressure in the first chamber, so that the secondary buffer can intervene faster and provide a uniform and stable buffering force, that is, reducing the rigid impact and ensuring the stability of the rice needle forming. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 is an exploded view of the present invention; Figure 3 is a top view of the present invention; Figure 4 This invention Figure 3 Cross-sectional view at AA in the middle; Figure 5 This invention Figure 4 Cross-sectional view at point C in the middle; Figure 6 This invention Figure 3 Cross-sectional view at the middle BB; Figure 7 It is a schematic diagram of the partial structure inside the lower mold of the present invention; The symbols in the figure are as follows: 1, upper mold; 2, upper template; 3, core; 4, lower mold; 5, first chamber; 6, lower template; 7, cavity; 8, first guide column; 9, first guide cylinder; 90, first annular protrusion; 10, second chamber; 11, pre-buffer unit; 110, first piston; 111, embedded hole; 112, first spring; 113, air inlet; 114, first one-way valve; 12, secondary buffer unit; 12 0. Second piston; 121. Second spring; 13. One-way unloading assembly; 130. Connecting channel; 131. Second one-way valve; 14. Ejector plate; 15. Drive unit; 150. Ejector column; 151. Sealing ring; 16. Exhaust unit; 160. Countersunk hole; 161. Exhaust hole; 17. Air vent; 18. Annular groove; 19. Second annular protrusion; 20. Second guide column; 21. Guide hole; 22. Second guide cylinder. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0021] Example 1: This embodiment provides a rice seedling needle punching and forming device, comprising: The upper mold 1 is provided with an upper template 2, and a core 3 for forming the rice seedling needles is provided on the upper template 2; The lower mold 4 is provided with a first cavity 5, and a lower template 6 is movably provided in the first cavity 5, and a cavity 7 is provided on the lower template 6 to match the core 3 and be used for forming the rice seedlings; The first guide post 8 is provided on the upper mold 1, and the lower mold 4 is provided with a first guide cylinder 9 adapted to the first guide post 8, and a second cavity 10 is formed in the first guide cylinder 9; The multi-stage buffer assembly includes a pre-buffer unit 11 and a secondary buffer unit 12. The pre-buffer unit 11 is disposed in the second chamber 10 and performs pre-buffering between the upper mold 1 and the lower mold 4 by compressing the gas in the second chamber 10. The secondary buffer unit 12 is disposed in the first chamber 5 and performs secondary buffering between the upper mold 2 and the lower mold 6 by compressing the gas in the first chamber 5. a one-way unloading assembly 13 connecting the first chamber 5 and the second chamber 10 and allowing only one-way flow of gas from the second chamber 10 into the first chamber 5 to transfer the compressive load of the second chamber 10 to the first chamber 5; The volume of the first chamber 5 is larger than that of the second chamber 10, so as to reduce the peak value of the buffer reaction force through a larger buffer space; At the same time, the gas can be air, which is convenient to obtain and discharge, without having to consider issues such as emissions; Furthermore, there are four first guide posts 8 , first guide cylinders 9 , second chambers 10 , pre-buffer units 11 and one-way unloading components 13 , which are respectively located at the four corners close to the lower mold 4 .

[0022] It can be seen from this embodiment that the first guide column 8 performs pre-buffering, and the secondary buffer unit performs secondary buffering between the upper template 2 with the core 3 and the lower template 6 with the cavity 7, thereby ensuring multiple buffering effects and improving mold clamping stability: The gas in the second chamber 10 used for buffering the first guide column 8 is directed into the first chamber 5 through the one-way unloading component 13, thereby reducing the pressure peak in the second chamber 10, avoiding overload of the pre-buffer unit 11, protecting the structural integrity of the pre-buffer unit 11, extending its service life, and avoiding deformation of the first guide column 8 and the mold or loosening of fasteners.

[0023] Example 2: This embodiment provides a rice seedling needle punching and forming device, which, in addition to the technical solutions of the above embodiments, also has the following technical features: the pre-buffer unit 11 includes: The first piston 110 is slidably connected to the inner wall of the second chamber 10; The first spring 112 is installed in the second chamber 10, with its two ends respectively abutting against the first piston 110 and the bottom wall of the second chamber 10; The lower mold 4 is provided with an air inlet 113 communicating with the second cavity 10 , and a first one-way valve 114 is provided at the air inlet 113 ; At the same time, the first one-way valve 114 includes a valve body, a spherical valve core and a spring, as shown in the accompanying drawings. It is a conventional one-way valve structure in the relevant technical field and will not be described in detail in this application.

[0024] As can be seen from this embodiment, the first piston 110 is used to compress the gas in the second chamber 10, thereby achieving a buffering effect on the downward movement of the upper mold 1, and the first spring 112 is used to push the first piston 110 to return after the mold is opened, and to extract air from the production environment through the first one-way valve 114. Therefore, the restoring force of the first spring 112 is greater than the spring compression force in the first one-way valve 114. In addition, the first spring 112 can also provide a certain buffering force in the pre-buffering stage, effectively ensuring the buffering effect of the pre-buffering.

[0025] Example 3: This embodiment provides a rice seedling needle punching and forming device, which, in addition to the technical solutions of the above embodiments, also has the following technical features: The top of the first piston 110 is provided with an embedding hole 111 adapted to the first guide column 8; The static friction resistance between the surface of the first guide column 8 and the inner wall of the embedded hole 111 is greater than the static friction resistance between the surface of the first piston 110 and the inner wall of the second chamber 10, and a first annular protrusion is provided at the top of the first guide cylinder 9 for limiting the first piston 110 from separating from the second chamber 10; The first annular protrusion and the first guide cylinder 9 may be in an integrated structure, and the first guide cylinder 9 and the lower mold 4 may be in an interference fit. At the same time, in order to make the static friction resistance between the surface of the first guide column 8 and the inner wall of the embedded hole 111 greater than the static friction resistance between the surface of the first piston 110 and the inner wall of the second chamber 10, this can be achieved by providing a rubber layer on the inner wall of the embedded hole 111. This is a conventional operation in the relevant technical field and will not be described in detail in this application.

[0026] It can be seen from the present embodiment that, by opening the embedding hole 111 and the static friction resistance between the first guide column 8 and the inner wall of the embedding hole 111 being greater than the static friction resistance between the surface of the first piston 110 and the inner wall of the second chamber 10, the reset of the first piston 110 can be ensured, and the situation in which the first piston 110 cannot be reset or the first one-way valve 114 cannot be opened due to elastic fatigue of the first spring 112 can be avoided, thereby effectively extending the effective time and service life of the pre-buffer unit 11.

[0027] Example 4: This embodiment provides a rice seedling needle punching and forming device, which, in addition to the technical solutions of the above embodiments, also has the following technical features: The one-way unloading assembly 13 includes a communication channel 130 communicating with the first chamber 5 and the second chamber 10, and a second one-way valve 131 is installed in the communication channel 130; The second one-way valve 131 is used to connect the second chamber 10 to the first chamber 5 and block the reverse direction. Meanwhile, the second one-way valve 131 can also adopt a structure of a valve body, a spherical valve core and a spring, as shown in the accompanying drawings, which is a conventional one-way valve structure in the relevant technical field and will not be described in detail in this application; Furthermore, in order to open the connecting channel 130, the lower mold 4 may include a first part and a second part, and the two parts are fastened with bolts, and a sealing groove arranged around the first cavity 5, the second cavity 10 and the connecting channel 130 and a sealing strip installed in the sealing groove are provided between the two parts.

[0028] It can be seen from this embodiment that the second one-way valve 131 allows only the gas in the second chamber 10 to flow into the first chamber 5 in one direction, and the volume of the first chamber 5 is larger. The gas is transferred to the first chamber 5 through the second chamber 10, so that when the core 3 and the blank are in contact with the first chamber 5, the first chamber 5 has a certain pressure, thereby avoiding a sudden increase in the pressure in the first chamber 5, so that the secondary buffer can intervene faster and provide a uniform and stable buffering force, that is, reducing the rigid impact and ensuring the stability of the rice seedling forming.

[0029] Example 5: This embodiment provides a rice seedling needle punching and forming device, which, in addition to the technical solutions of the above embodiments, also has the following technical features: the secondary buffer unit 12 includes: The second piston 120 is mounted on a side of the lower mold plate 6 close to the first chamber 5 and is slidably connected to the inner wall of the first chamber 5; The second spring 121 is installed in the first chamber 5 , and its two ends are respectively in contact with the second piston 120 and the bottom wall of the first chamber 5 .

[0030] It can be seen from this embodiment that the provision of the second piston 120 facilitates the abutment of the upper template 2 against the lower template 6 to cause the second piston 120 to compress the first chamber 5, thereby providing a buffering force, and the second spring 121 can provide a certain buffering force during the secondary buffering, effectively ensuring the buffering effect of the secondary buffering.

[0031] Example 6: This embodiment provides a rice seedling needle punching and forming device, which, in addition to the technical solutions of the above embodiments, also has the following technical features, including: The ejector assembly is installed in the lower mold plate 6 and includes an ejector plate 14, a drive unit 15 and an exhaust unit 16, and a vent hole 17 is opened through the second piston 120 and the lower mold plate 6; After the core 3 releases the restriction on the ejector plate 14, the driving unit 15 provides driving force through the vent hole 17 by the pressure difference between the inside and outside of the first chamber 5 to push the ejector plate 14; The exhaust unit 16 is used to discharge the compressed gas in the first chamber 5 after a single stamping process; At the same time, a sealing ring 151 is provided between the lower template 6 and the second piston 120 to ensure the sealing performance of the first chamber 5; In addition, the top plate 14 may also be provided with a protrusion or groove structure for forming the seedling needles, which is a conventional setting made by technicians in the relevant technical field to punch out a specific seedling needle shape, and will not be described in detail in this application.

[0032] It can be seen from this embodiment that the internal and external pressure difference generated by the buffering of the first chamber 5 can be used as a driving force to push the ejector plate 14 to jack up, thereby avoiding the situation where the finished seedling needles and the cavity 7 are stuck after stamping, and effectively ensuring the convenience of unloading. The exhaust unit 16 is convenient for discharging the compressed gas in the first chamber 5 after a single needle is formed, so as to provide a buffering effect for the next punching, and at the same time avoid the continuous accumulation of compressed gas in the first chamber 5, thereby ensuring the stability and sustainability of the system.

[0033] Example 7: This embodiment provides a rice seedling needle punching and forming device, which, in addition to the technical solutions of the above embodiments, also has the following technical features: The driving unit 15 includes a push rod 150 slidably connected to the air vent 17 and a sealing ring 151 installed between the ejector plate 14 and the bottom wall of the cavity 7, and the sealing ring 151 is used to seal one end of the air vent 17; The vent hole 17 is a stepped hole, and the axial dimension of the stepped hole is larger than the axial dimension of the top column 150. An annular groove 18 is formed on the inner wall of the vent hole 17, and a second annular protrusion 19 for sliding along the annular groove 18 is formed on the surface of the top column 150. At the same time, the second annular protrusion 19 and the top column 150 adopt an integrated structure, and the sealing ring 151 is arranged around the circumference of the air vent 17 and can be made of rubber. Furthermore, the ejector column 150 and the ejector plate 14 may be fixedly connected, specifically by welding or bolt fastening.

[0034] As can be seen in this embodiment, by adopting the ejector pin 150 as the driving unit 15, the ejector pin 150 is pushed to slide in the vent hole 17 by the pressure difference. With the provision of the sealing ring 151, the first chamber 5 is in a sealed environment when the ejector plate 14 abuts against the bottom wall of the cavity 7, thereby ensuring the formation of compressed gas and facilitating buffering. The annular groove 18 provided on the inner wall of the air vent 17 and the second annular protrusion 19 provided on the surface of the top column 150 for sliding along the annular groove 18 can prevent the pressure difference from pushing the top column 150 away from the air vent 17, thereby ensuring stability.

[0035] Example 8: This embodiment provides a rice seedling needle punching and forming device, which, in addition to the technical solutions of the above embodiments, also has the following technical features: The exhaust unit 16 includes a counterbore 160 axially opened in the top column 150 and an exhaust hole 161 opened on the inner wall of the counterbore 160 ; Among them, the exhaust hole 161 is located on the side of the top column 150 close to the top plate 14, and after the annular groove 18 and the second annular protrusion 19 abut and restrict, a vent hole extends from the end of the top column 150 located at the exhaust hole 161, and the exhaust speed of the exhaust hole 161 is slower than the gas transfer speed from the second chamber 10 to the first chamber 5.

[0036] It can be seen from this embodiment that the provision of the exhaust holes 161 facilitates the discharge of the compressed gas in the first chamber 5 after the top column 150 is lifted by the compressed gas. On the one hand, this facilitates the lifting of the formed seedling needles, and on the other hand, it enables the first chamber 5 to return to normal pressure, which is convenient for the next buffer. Moreover, the provision of the countersunk holes 160 enables the exhaust holes 161 to be radially opened, thereby facilitating the adjustment of the number of the exhaust holes 161. Since there are four first guide columns 8, first guide cylinders 9, and second chambers 10, the total exhaust speed of all the exhaust holes 161 can be made slower than the gas transfer speed from the four second chambers 10 to the first chamber 5 by controlling the number and size of the exhaust holes 161. The exhaust speed of the exhaust unit 16 is lower than the speed at which the gas in the second chamber 10 flows to the first chamber 5. Therefore, the gas in the second chamber 10 can gradually and steadily fill the first chamber 5, so that the first chamber 5 slowly rises from normal pressure, so that the pressure difference between the two chambers is always within a controllable range, avoiding the impact caused by the sudden influx of high-pressure gas, and improving the stability of the overall buffer system.

[0037] Example 9: This embodiment provides a rice seedling needle punching and forming device, which, in addition to the technical solutions of the above embodiments, also has the following technical features, including: The second guide post 20 is mounted on the lower mold plate 6, and the lower mold 4 is provided with a guide hole 21 corresponding to the second guide post 20; The second guide cylinder 22 is installed in the guide hole 21 and is adapted to the second guide column 20 .

[0038] It can be seen from this embodiment that the provision of the second guide column 20 and the second guide cylinder 22 can improve the stability and accuracy of the lifting and lowering of the lower template 6 and ensure the stability of the buffer.

[0039] Example 10: This embodiment provides a stamping process of a seedling needle stamping forming device, comprising the following steps: S1: placing a rice seedling blank on the cavity 7 and driving the upper mold 1 to move it close to the lower mold 4 for mold closing; S2: After the first guide column 8 enters the first guide cylinder 9, the pre-buffer unit 11 is pre-triggered and pre-buffered. During the pre-buffering process, the gas in the second chamber 10 is compressed and gradually guided to the first chamber 5. S3: When the core 3 on the upper template 2 contacts the seedling needle blank and pushes the ejector plate 14 to squeeze the sealing ring 151, the first chamber 5 forms a sealed space; S4: The upper template 2 pushes the lower template 6 downward and compresses the first chamber 5. At the same time, the gas in the second chamber 10 is continuously squeezed into the first chamber 5. S5: When the gas pressure in the second chamber 10 is lower than the gas pressure in the first chamber 5, the second one-way valve 131 is closed, and the first chamber 5 continues to be compressed until the rice seedlings are formed; S6: The upper mold 1 moves upward to move away from the lower mold 4 for mold opening; S7: The first guide column 8 drives the first piston 110 to return to its original position and opens the first one-way valve 114 to inhale air; S8: The core 3 releases the contact between the seedling needles and the ejector plate 14, and the compressed gas in the first chamber 5 pushes the ejector column 150 through the air vent 17 to lift the ejector plate 14 and the finished seedling needles; S9: The compressed gas in the first chamber 5 is discharged through the exhaust hole 161, and steps S1 to S9 are repeated.

[0040] As can be seen from this embodiment, the above-mentioned stamping process can effectively ensure the cushioning effect and uniformity when stamping the seedling needles, reduce the pressure peak of the second chamber 10, avoid overloading of the pre-buffer unit 11, and control the maximum air pressure of the second chamber 10 within a safe threshold, thereby protecting the structural integrity of the pre-buffer unit 11 and extending its service life. At the same time, sudden pressure changes during the buffering stage are avoided. The one-way valve only allows the gas in the second chamber 10 to flow into the first chamber 5 in one direction. Since the first chamber 5 has a larger volume, the gas in the second chamber 10 can gradually and smoothly fill the first chamber 5, so that the pressures of the first chamber 5 and the second chamber 10 are always within a controllable range. This allows for a smooth transition from the pre-buffering stage to the secondary buffering stage, avoiding impacts on the mold caused by sudden pressure changes and improving the stability of the overall buffering system. And after the gas in the second chamber 10 is transferred to the first chamber 5, the first chamber 5 can have a certain basic air pressure before entering the secondary buffer. When it enters the secondary buffer, the first chamber 5 is compressed, which can make the air pressure rise steadily, avoiding the sudden pressure rise caused by compression under normal pressure, so that the secondary buffer can intervene faster and provide uniform buffering force, which not only avoids the rigid impact of the mold, but also ensures the force stability during the formation of the rice seedlings and guarantees the stamping accuracy.

[0041] The embodiments of the present application are described above in conjunction with the accompanying drawings. Unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. A rice seedling needle stamping and forming device, characterized in that: include: An upper mold (1) is provided with an upper template (2), and a core (3) for forming rice seedling needles is provided on the upper template (2); The lower mold (4) is provided with a first cavity (5), and a lower template (6) is movably provided in the first cavity (5), and a cavity (7) is provided on the lower template (6) and is adapted to the core (3) and used for forming the rice seedlings; A first guide column (8) is provided on the upper mold (1), and the lower mold (4) is provided with a first guide cylinder (9) adapted to the first guide column (8), and a second cavity (10) is formed in the first guide cylinder (9); A multi-stage buffer assembly comprises a pre-buffer unit (11) and a secondary buffer unit (12), wherein the pre-buffer unit (11) is arranged in the second chamber (10) and performs pre-buffering between the upper mold (1) and the lower mold (4) by compressing the gas in the second chamber (10), and the secondary buffer unit (12) is arranged in the first chamber (5) and performs secondary buffering between the upper mold (2) and the lower mold (6) by compressing the gas in the first chamber (5); a one-way unloading assembly (13) connecting the first chamber (5) and the second chamber (10) and allowing only one-way flow of gas from the second chamber (10) into the first chamber (5) to transfer the compression load of the second chamber (10) to the first chamber (5); The volume of the first chamber (5) is greater than the volume of the second chamber (10), so as to reduce the peak value of the buffering reaction force through a larger buffer space.

2. The rice seedling needle punching and forming device according to claim 1, characterized in that: The pre-buffer unit (11) comprises: A first piston (110) is slidably connected to the inner wall of the second chamber (10), and has an embedding hole (111) at its top end adapted to fit the first guide column (8); A first spring (112) is installed in the second chamber (10), with two ends respectively contacting the first piston (110) and the bottom wall of the second chamber (10); The lower mold (4) is provided with an air inlet (113) communicating with the second chamber (10), and a first one-way valve (114) is provided at the air inlet (113).

3. The rice seedling needle punching and forming device according to claim 2, characterized in that: The static friction resistance between the surface of the first guide column (8) and the inner wall of the embedded hole (111) is greater than the static friction resistance between the surface of the first piston (110) and the inner wall of the second chamber (10), and a first annular protrusion (90) for limiting the first piston (110) from separating from the second chamber (10) is provided at the top end of the first guide cylinder (9).

4. The rice seedling needle punching and forming device according to claim 1, characterized in that: The one-way unloading assembly (13) comprises a communication channel (130) communicating with the first chamber (5) and the second chamber (10), and a second one-way valve (131) is installed in the communication channel (130); The second one-way valve (131) is used to conduct the second chamber (10) to the first chamber (5) and to block the reverse direction.

5. The rice seedling needle punching and forming device according to claim 1, characterized in that: The secondary buffer unit (12) comprises: A second piston (120) is mounted on a side of the lower template (6) close to the first chamber (5) and is slidably connected to the inner wall of the first chamber (5); The second spring (121) is installed in the first chamber (5), and its two ends are respectively in contact with the second piston (120) and the bottom wall of the first chamber (5).

6. The rice seedling needle punching and forming device according to claim 5, characterized in that: Also includes: A ejector assembly is installed in the lower mold plate (6) and includes an ejector plate (14), a drive unit (15) and an exhaust unit (16), and an air vent (17) is provided through the second piston (120) and the lower mold plate (6); After the core (3) releases the restriction on the ejector plate (14), the driving unit (15) provides a driving force through the air vent (17) by the pressure difference between the inside and outside of the first chamber (5) to push the ejector plate (14); The exhaust unit (16) is used to exhaust the compressed gas in the first chamber (5) after a single stamping process.

7. The rice seedling needle punching and forming device according to claim 6, characterized in that: The driving unit (15) includes a top column (150) slidably connected in the vent hole (17) and a sealing ring (151) installed between the ejector plate (14) and the bottom wall of the cavity (7), and the sealing ring (151) is used to seal one end of the vent hole (17); The air vent (17) is a stepped hole, and the axial dimension of the air vent (17) is larger than the axial dimension of the top column (150). An annular groove (18) is provided on the inner wall of the air vent (17), and a second annular protrusion (19) for sliding along the annular groove (18) is provided on the surface of the top column (150).

8. The rice seedling needle punching and forming device according to claim 6, characterized in that: The exhaust unit (16) comprises a countersunk hole (160) axially opened in the top column (150) and an exhaust hole (161) opened on the inner wall of the countersunk hole (160); The exhaust hole (161) is located on a side of the top column (150) close to the top plate (14), and the exhaust speed of the exhaust hole (161) is slower than the gas transfer speed from the second chamber (10) to the first chamber (5).

9. The rice seedling needle punching and forming device according to claim 1, characterized in that: Also includes: A second guide post (20) is mounted on the lower template (6), and a guide hole (21) corresponding to the second guide post (20) is provided on the lower mold (4); The second guide cylinder (22) is installed in the guide hole (21) and is adapted to the second guide column (20).

10. A stamping process applied to the rice seedling needle stamping and forming device according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: placing a rice seedling blank on the cavity (7), and driving the upper mold (1) to move it close to the lower mold (4) for mold closing; S2: After the first guide column (8) enters the first guide cylinder (9), the pre-buffer unit (11) is pre-triggered and pre-buffered. During the pre-buffering process, the gas in the second chamber (10) is compressed and gradually guided to the first chamber (5); S3: When the core (3) on the upper template (2) contacts the seedling needle blank and pushes the ejector plate (14) to squeeze the sealing ring (151), the first chamber (5) forms a sealed space; S4: The upper template (2) pushes the lower template (6) downward and compresses the first chamber (5), while the gas in the second chamber (10) is continuously squeezed into the first chamber (5); S5: When the gas pressure in the second chamber (10) is lower than the gas pressure in the first chamber (5), the second one-way valve (131) is closed, and the first chamber (5) continues to be compressed until the rice seedlings are formed; S6: the upper mold (1) moves upward to move away from the lower mold (4) to open the mold; S7: The first guide column (8) drives the first piston (110) to reset, and opens the first one-way valve (114) to inhale; S8: the core (3) releases the contact between the seedling needles and the ejector plate (14), and the compressed gas in the first chamber (5) pushes the ejector column (150) through the air vent (17) to lift the ejector plate (14) and the finished seedling needles; S9: The compressed gas in the first chamber (5) is discharged through the exhaust hole (161), and steps S1 to S9 are repeated.

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