A powder filling tool and its application method

Abstract

The present invention relates to the technical field of powder filling tooling, and specifically to a powder filling tooling and its application method. The powder filling tooling includes a shell, a base plate, an opening and closing mechanism, and a powder filling assembly; the powder filling assembly is arranged on the shell, and includes a column, an inner cylinder, and an outer cylinder coaxially arranged from the inside to the outside; in the opening and closing mechanism, an annular turntable is rotatably arranged in an annular cavity surrounded by the shell and the base plate; a plurality of guide holes are arranged on the annular turntable; a plurality of guide grooves are arranged on the base plate; the wide end of each blade is arranged between the annular turntable and the base plate, and a guide column adapted to the guide hole and a guide protrusion adapted to the guide groove are respectively provided on both sides of the wide end; the narrow end of each blade forms a polygonal opening with an adjustable opening size along the outer periphery of the column; a linkage rod is arranged on the annular turntable; a driving member is arranged on the shell, and its output end is connected to the linkage rod. The application method adopts the powder filling tooling to solve the problem of powder leakage and the problem of long process time.

Description

Technical Field

[0001] The present invention relates to the technical field of powder filling tooling, and in particular to a powder filling tooling and an application method thereof. Background Art

[0002] Existing brake disc blanks generally consist of coaxial, connected inner and outer annular brake discs. These disc blanks are formed in a forming mold using the following method: First, the upper mold in the forming mold is opened, and the lower mold is driven down along the outer female mold, while a core column coaxial with the lower mold is driven up, forming a forming cavity surrounded by the female mold and the core column. Subsequently, a spacer tool is coaxially placed within the female mold, dividing the forming cavity into an inner annular cavity (i.e., between the spacer tool and the core column) and an outer annular cavity (i.e., between the spacer tool and the inner wall of the female mold). Powder for forming the inner annular brake disc is then loaded into the inner annular cavity, while powder for forming the outer annular brake disc is loaded into the outer annular cavity. Finally, the spacer is removed, and the upper and lower molds are driven toward each other to complete the compaction of the powder, thereby forming the coaxial, connected inner and outer annular brake discs.

[0003] However, this forming method has the following problems: 1) When the spacer is pulled out, powder leakage easily occurs between the powder in the inner annular cavity and the powder in the outer annular cavity, resulting in the boundary line between the inner annular brake disc and the outer annular brake disc being an irregular ring line. It is difficult to form a uniform and consistent annular dividing line, resulting in poor appearance quality of the brake disc blank; 2) This forming method occupies the forming mold when filling powder into the inner annular cavity and the outer annular cavity, resulting in a time-consuming forming process.

[0004] In summary, it is necessary to develop a powder filling tool and an application method thereof to solve the problems existing in the prior art. Summary of the Invention

[0005] The present invention aims to provide a powder filling tool and an application method thereof, and the specific technical solutions are as follows:

[0006] In a first aspect, the present invention provides a powder filling tool, comprising a shell, a bottom plate, an opening and closing mechanism, and a powder filling assembly;

[0007] The powder filling assembly is arranged on the shell, and includes a cylinder, an inner cylinder and an outer cylinder; the outer cylinder is connected to the shell, and the area on the shell corresponding to the outer cylinder is a hollow area; the inner cylinder is coaxially arranged in the outer cylinder, and the two are connected to form an outer annular powder filling area; the cylinder is coaxially arranged in the inner cylinder, and the two are connected to form an inner annular powder filling area;

[0008] The bottom plate is arranged at the bottom of the shell, and the area of ​​the bottom plate corresponding to the outer tube is a hollow area; an annular cavity for the movement of the opening and closing mechanism is left between the bottom plate and the shell; the bottom end of the column extends below the hollow area of ​​the bottom plate and is lower than the bottom end of the inner tube;

[0009] The opening and closing mechanism includes a driving member and an opening and closing assembly; the opening and closing assembly includes an annular rotating disk and a plurality of blades; the annular rotating disk is rotatably arranged in the annular cavity; guide holes equal to the number of the blades are sequentially spaced in the circumferential direction of the annular rotating disk; guide grooves equal to the number of the blades are sequentially spaced in the circumferential direction of the bottom plate; each of the blades is arranged at the bottom of the inner cylinder and the outer cylinder; the two ends of each blade in the longitudinal direction are respectively a wide end and a narrow end, the wide end of which is arranged between the annular rotating disk and the bottom plate, and a guide column adapted to the guide hole and a guide protrusion adapted to the guide groove are respectively provided on the two side surfaces of the wide end; the narrow end of each blade is arranged in a hollow area between the bottom plate and the shell, and a polygonal opening with adjustable opening size is formed along the outer circumference of the column; a linkage rod is provided on the annular rotating disk, and a through hole for the linkage rod to pass through and move is provided on the shell; the driving member is provided on the shell, and its output end is connected to the linkage rod for linkage opening and closing of each blade.

[0010] Optionally, the guide hole includes a waist-shaped hole, one end of which is arranged close to the polygonal opening in the length direction, which is the proximal end, and the other end of which is arranged away from the polygonal opening in the length direction, which is the distal end; the angle α2 between the proximal end of the guide hole and the center of the circumscribed circle of the polygonal opening and the length direction of the guide hole is 50°~80°; the angle α1 between the distal end of the guide hole and the center of the circumscribed circle of the polygonal opening and the length direction of the guide hole is 20°~50°.

[0011] Optionally, one end of the guide groove in the length direction is arranged close to the polygonal opening, which is the proximal end, and the other end in the length direction is arranged away from the polygonal opening, which is the distal end; the angle α3 between the proximal end of the guide groove and the center of the circumscribed circle of the polygonal opening and the length direction of the guide groove is 60°~80°; the angle α4 between the distal end of the guide groove and the center of the circumscribed circle of the polygonal opening and the length direction of the guide groove is 40°~60°.

[0012] Optionally, an annular boss is further provided on the outer periphery of the bottom end of the column; the narrow end of each blade is provided close to or away from the annular boss.

[0013] Optionally, a circular arc chamfer adapted to the core hole of the forming die is provided on the bottom end of the column.

[0014] Optionally, the number of the blades is 10 to 20. The more blades there are, the more circular the opening formed by the narrow end of each blade along the outer circumference of the cylinder becomes, which is beneficial to preventing powder from flowing out and forming a uniform annular dividing line at the interface of the product.

[0015] Each of the blades includes an integrally formed triangular piece and a square piece; an end of the triangular piece away from the square piece is the narrow end, and an end of the square piece away from the triangular piece is the wide end;

[0016] A circular arc chamfer is provided at the connection between the square piece and the triangular piece; and a circular arc chamfer is provided at one end of the square piece away from the triangular piece.

[0017] Optionally, a movable gap is set between the blade and the inner cylinder and between the blade and the outer cylinder; the spacing of the movable gap is 0.3~0.5mm.

[0018] Optionally, the driving member includes a cylinder.

[0019] In a second aspect, the present invention provides an application method of the powder filling tool, which comprises:

[0020] Step S1: Start the driving member to drive the linkage rod, thereby sequentially linking the annular turntable and the blades to ensure that the narrow end of each blade is in close contact with the outer circumference of the cylinder to close the bottom of the inner cylinder and the outer cylinder; fill powder to the target height in the inner annular powder filling area and the outer annular powder filling area of ​​the powder filling tool; vibrate the powder filling tool during the powder filling process to ensure that the filled powder is dense;

[0021] Step S2, opening the upper mold of the forming mold, positioning the powder-filled powder filling tool with the bottom end of the cylinder into the core hole of the lower mold of the forming mold; starting the driving member to drive the linkage rod, and then sequentially linking the annular turntable and the blades to gradually expand the polygonal opening surrounded by the narrow ends of the blades, thereby gradually opening the bottoms of the inner cylinder and the outer cylinder; at the same time, controlling the lower mold of the forming mold to descend along the female mold coaxially arranged outside the female mold, driving the core column coaxial with the lower mold to rise along the core hole, and forming a negative pressure forming cavity surrounded by the female mold and the core column, and filling the powder into the forming cavity in a suction manner;

[0022] Step S3: After the filling is completed, the powder filling tool is removed, the upper mold is closed, and the upper mold and the lower mold are driven to move toward each other to complete the pressing and forming operation of the powder to form a formed green body product.

[0023] Optionally, the target height is twice the height of the formed green body product; the pressure used in the pressing is 150-200 MPa;

[0024] The driving member drives the linkage rod to move at a speed of 20-100 mm / s;

[0025] The lower die descends at a speed of 20-50 mm / s.

[0026] The application of the technical solution of the present invention has at least the following beneficial effects:

[0027] The present invention provides a powder filling tool and its application method, which can not only solve the problem of powder leakage after powder filling, so that the product forms a uniform and consistent annular dividing line at the interface, but also solve the problem that the existing powder filling tool fills powder completely in the forming mold, resulting in a long forming process. Specifically, first, the present invention uses a powder filling tool to complete the powder filling operation outside the forming mold, that is, start the driving member to drive the linkage rod, and then sequentially link the annular turntable and each of the blades to achieve that the narrow end of each blade is close to the outer periphery of the cylinder to close the bottom of the inner cylinder and the outer cylinder; the powder filling operation is completed in the inner annular powder filling area and the outer annular powder filling area of ​​the powder filling tool respectively; secondly, the present invention uses a powder filling tool to complete the powder filling operation of the forming mold in the forming mold, that is, open the upper mold of the forming mold, and insert the powder filling tool after powder filling into the lower mold core hole of the forming mold with the bottom end of the cylinder positioned; start the driving member to drive the linkage rod, and then sequentially link the annular turntable and each of the blades to achieve that the polygonal opening surrounded by the narrow end of each blade is gradually expanded, and then gradually opened. The bottom of the inner and outer cylinders is opened, and at the same time, the lower mold of the forming mold is controlled to descend along the female mold coaxially arranged outside thereof, and the core column coaxial with the lower mold is driven to rise along the core hole, and the female mold and the core column form a negative pressure forming cavity, and the powder is filled into the forming cavity by suction under negative pressure conditions; therefore, the polygonal opening surrounded by each blade used in the opening and closing assembly of the present invention always forms a polygonal opening that is approximately circular under the driving action of the driving member and the use of guide holes and guide grooves to provide dual guidance for the blades, which is convenient for adapting to the opening of the inner and outer cylinders, and combined with the negative pressure suction powder filling, so that when the powder in the powder filling tool is filled into the forming mold, the powder mixing between the inner annular powder and the outer annular powder in the forming cavity is effectively solved, so that the product forms a uniform and consistent annular dividing line at the interface. In addition, the present invention uses the powder filling tool to complete the powder filling operation outside the forming mold and then fills the forming mold with powder, which can solve the problem that the existing powder filling tool fills the powder completely inside the forming mold, resulting in a long forming process.

[0028] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 2 is a schematic cross-sectional view of a powder filling tool in an embodiment;

[0031] Figure 2 Schematic diagram of the structure of the opening and closing mechanism and the bottom plate combination in the embodiment;

[0032] Figure 3 It is a structural diagram of the combination of all blades and base plates;

[0033] Figure 4 It is a schematic diagram of the structure of the blade;

[0034] Figure 5 It is the angle between the line connecting the proximal end and the distal end of any guide hole on the annular turntable and the center of the circumscribed circle of the polygonal opening and the length direction of the guide hole;

[0035] Figure 6 It is a schematic diagram of the cross-sectional structure of the powder filling tooling applied to the forming die;

[0036] Among them, 1. Shell, 2. Bottom plate, 2.1. Guide groove, 3. Opening and closing mechanism, 3.1. Driving part, 3.2. Annular turntable, 3.2.1. Guide hole, 3.2.2. Linkage rod, 3.3. Blade, 3.3.1. Guide column, 3.3.2. Guide protrusion, 4. Powder filling assembly, 4.1. Cylinder, 4.1.1. Annular boss, 4.2. Inner cylinder, 4.3. Outer cylinder, A1. Upper mold, A2. Lower mold, A3. Female mold, A4. Core column. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0038] Example 1:

[0039] See also Figures 1 to 5 , a powder filling tool, comprising a shell 1, a bottom plate 2, an opening and closing mechanism 3 and a powder filling component 4;

[0040] The powder filling assembly 4 is disposed on the housing 1 and includes a cylinder 4.1, an inner cylinder 4.2, and an outer cylinder 4.3. The outer cylinder 4.3 is connected to the housing 1, and the area on the housing 1 corresponding to the outer cylinder 4.3 is a hollow area. The inner cylinder 4.2 is coaxially disposed within the outer cylinder 4.3, and the two are connected by a connecting plate, forming an outer annular powder filling area. The cylinder 4.1 is coaxially disposed within the inner cylinder 4.2, and the two are connected by a connecting plate, forming an inner annular powder filling area.

[0041] The bottom plate 2 is disposed at the bottom of the housing 1, and the area of ​​the bottom plate 2 corresponding to the outer cylinder 4.3 is a hollow area. An annular cavity is left between the bottom plate 2 and the housing 1 for the movement of the opening and closing mechanism 3. The bottom end of the column 4.1 extends below the hollow area of ​​the bottom plate 2 and is lower than the bottom end of the inner cylinder 4.2, thereby completely isolating the inner cylinder 4.2 into an inner annular powder filling area.

[0042] The opening and closing mechanism 3 includes a driving member 3.1 (specifically a cylinder) and an opening and closing assembly; the opening and closing assembly includes an annular turntable 3.2 and a plurality of blades 3.3 (the number of blades 3.3 is 12, which is convenient for forming a polygonal opening that is approximately circular); the annular turntable 3.2 is rotatably arranged in the annular cavity; guide holes 3.2.1 equal to the number of the blades 3.3 are sequentially spaced in the circumferential direction of the annular turntable 3.2; guide grooves 2.1 equal to the number of the blades 3.3 are sequentially spaced in the circumferential direction of the bottom plate 2; each of the blades 3.3 is arranged at the bottom of the inner cylinder 4.2 and the outer cylinder 4.3; the two ends of each blade 3.3 in the length direction are respectively a wide end and a narrow end, the wide end of which is arranged between the annular turntable 3.2 and the bottom plate 2, and guide columns 3.3.1 adapted to the guide holes 3.2.1 and guide grooves 2.1 adapted to the guide holes 3.2.1 are respectively provided on both side surfaces of the wide end. The guide protrusion 3.3.2 is adapted to the groove 2.1; the narrow end of each of the blades 3.3 is arranged in the hollow area between the bottom plate 2 and the shell 1, and a polygonal opening with adjustable opening size is formed along the outer periphery of the cylinder 4.1; a linkage rod 3.2.2 is provided on the annular turntable 3.2, and a through hole for the linkage rod 3.2.2 to pass through and move is provided on the shell 1; the driving member 3.1 is provided on the shell 1, and its output end is connected to the linkage rod 3.2.2 for linking the opening and closing of each of the blades 3.3, which not only enables the narrow end of each of the blades 3.3 to be tightly against the outer periphery of the cylinder 4.1 to close the bottom of the inner cylinder 4.2 and the outer cylinder 4.3, facilitating powder filling in the powder filling tooling, but also enables the polygonal opening surrounded by the narrow ends of each of the blades 3.3 to gradually expand, thereby gradually opening the bottom of the inner cylinder 4.2 and the outer cylinder 4.3, completing the powder filling operation of the forming mold.

[0043] See also Figure 5 The guide hole 3.2.1 includes a waist-shaped hole, one end of which is close to the polygonal opening in the length direction, which is the proximal end, and the other end of which is far away from the polygonal opening in the length direction, which is the distal end; the angle between the line connecting the proximal end of the guide hole 3.2.1 and the center of the circumscribed circle of the polygonal opening and the length direction of the guide hole 3.2.1 is 65° (i.e. α2); the angle between the line connecting the distal end of the guide hole 3.2.1 and the center of the circumscribed circle of the polygonal opening and the length direction of the guide hole 3.2.1 is 40° (i.e. α1).

[0044] One end of the guide groove 2.1 in the length direction is arranged close to the polygonal opening, which is the proximal end, and the other end thereof in the length direction is arranged away from the polygonal opening, which is the distal end; the angle α3 formed by the line connecting the proximal end of the guide groove 2.1 and the center of the circumscribed circle of the polygonal opening and the length direction of the guide groove 2.1 is 70°; the angle α4 formed by the line connecting the distal end of the guide groove 2.1 and the center of the circumscribed circle of the polygonal opening and the length direction of the guide groove 2.1 is 50°.

[0045] The angles of the guide holes 3.2.1 and the guide slots 2.1 are set so that each blade 3.3 always forms a substantially circular polygonal opening when driven by the driver 3.1, and ensures that each blade 3.3 does not interfere with each other when driven by the driver 3.1. In this embodiment, the guide holes 3.2.1 and the guide slots 2.1 provide dual guidance for the blades 3.3, ensuring that each blade 3.3 always forms a substantially circular polygonal opening when driven by the driver 3.1.

[0046] See also Figure 1 , an annular boss 4.1.1 is further provided on the outer periphery of the bottom end of the column 4.1; the narrow end of each blade 3.3 is arranged close to or away from the annular boss 4.1.1; when the narrow end of each blade 3.3 is close to and tightly attached to the annular boss 4.1.1, the annular boss 4.1.1 provides support for the narrow end of the blade 3.3, thereby improving the stability during the powder filling operation in the powder filling tooling.

[0047] See also Figure 1 A circular chamfer that matches the core hole of the forming mold is provided on the bottom end of the column 4.1 to facilitate the installation of the powder filling tool on the forming mold.

[0048] See also Figure 3~Figure 4 , each of the blades 3.3 comprises an integrally formed triangular piece and a square piece; the end of the triangular piece away from the square piece is the narrow end, and the end of the square piece away from the triangular piece is the wide end;

[0049] A circular chamfer is provided at the connection between the square piece and the triangular piece, and a circular chamfer is provided at the end of the square piece away from the triangular piece. The circular chamfer is provided to ensure that the blades 3.3 do not interfere with each other when driven by the driving member 3.1.

[0050] A movable gap is set between the blade 3.3 and the inner cylinder 4.2, and between the blade 3.3 and the outer cylinder 4.3; the spacing of the movable gap is 0.3~0.5mm, which not only facilitates the smooth opening and closing operation of the blade 3.3 under the driving action of the driving member 3.1, avoids the inner cylinder 4.2 and the outer cylinder 4.3 from wearing the blade 3.3, but also avoids powder leakage between the inner annular powder filling area and the outer annular powder filling area.

[0051] See also Figure 1 and Figure 6 The application method of the powder filling tool comprises:

[0052] Step S1: Start the driving member 3.1 to drive the linkage rod 3.2.2, thereby sequentially linking the annular turntable 3.2 and the blades 3.3 so that the narrow end of each blade 3.3 is in close contact with the outer circumference of the cylinder 4.1 to close the bottom of the inner cylinder 4.2 and the outer cylinder 4.3; fill powder to the target height in the inner annular powder filling area and the outer annular powder filling area of ​​the powder filling tool; vibrate the powder filling tool during the powder filling process to ensure that the filled powder is dense;

[0053] Step S2, opening the upper die A1 of the forming die, inserting the powder-filled powder filling tooling into the core hole of the lower die A2 of the forming die with the bottom end of the column 4.1 positioned therein; starting the driving member 3.1 to drive the linkage rod 3.2.2, thereby sequentially linking the annular turntable 3.2 and the blades 3.3 to gradually expand the polygonal opening formed by the narrow ends of the blades 3.3, thereby gradually opening the bottoms of the inner cylinder 4.2 and the outer cylinder 4.3; at the same time, controlling the lower die A2 of the forming die to descend along the female die A3 coaxially arranged outside the lower die A2, driving the core column A4 coaxial with the lower die A2 to ascend along the core hole, and forming a negative pressure forming cavity surrounded by the female die A3 and the core column A4, and filling the powder into the forming cavity by suction;

[0054] Step S3: After the filling is completed, the powder filling tool is removed, the upper mold A1 is closed, and the upper mold A1 and the lower mold A2 are driven to move toward each other to complete the pressing and forming operation of the powder to form a formed green body product (such as a brake disc).

[0055] In order to form a shaped green body product, the target height is twice the height of the shaped green body product; the pressure used in the press forming is 180 MPa.

[0056] In order to avoid powder leakage, the driving member 3.1 drives the linkage rod 3.2.2 to move at a speed of 50 mm / s; the lower mold A2 descends at a speed of 25 mm / s.

[0057] In order to meet the specific shape requirements of some formed green products, it is necessary to set a shape that adapts to the specific shape on the lower mold A2 and / or the upper mold A1, such as setting a gooseneck protrusion on the lower mold A2.

[0058] The polygonal opening formed by the blades 3.3 in the opening and closing assembly of this embodiment always forms a nearly circular polygonal opening under the driving action of the driving member 3.1 and the dual guiding action provided by the guide holes 3.2.1 and the guide grooves 2.1 for the blades 3.3, so as to facilitate the adaptation arrangement with the openings of the inner cylinder 4.2 and the outer cylinder 4.3. Combined with the negative pressure suction powder filling, the powder in the powder filling tool is effectively solved when the powder is filled into the forming mold, so that the powder is effectively solved between the inner annular powder and the outer annular powder in the forming cavity, so that the product forms a uniform and consistent annular dividing line at the interface. In addition, the present invention uses the powder filling tool to complete the powder filling operation outside the forming mold before filling the forming mold with powder, which can solve the problem that the existing powder filling tool fills the powder completely inside the forming mold, resulting in a long forming process.

[0059] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A powder filling tool, characterized in that: It includes a shell, a bottom plate, an opening and closing mechanism and a powder filling component; The powder filling assembly is arranged on the shell, and includes a cylinder, an inner cylinder and an outer cylinder; the outer cylinder is connected to the shell, and the area on the shell corresponding to the outer cylinder is a hollow area; the inner cylinder is coaxially arranged in the outer cylinder, and the two are connected to form an outer annular powder filling area; the cylinder is coaxially arranged in the inner cylinder, and the two are connected to form an inner annular powder filling area; The bottom plate is arranged at the bottom of the shell, and the area of ​​the bottom plate corresponding to the outer tube is a hollow area; an annular cavity for the movement of the opening and closing mechanism is left between the bottom plate and the shell; the bottom end of the column extends below the hollow area of ​​the bottom plate and is lower than the bottom end of the inner tube; The opening and closing mechanism includes a driving member and an opening and closing assembly; the opening and closing assembly includes an annular turntable and a plurality of blades; the annular turntable is rotatably arranged in the annular cavity; Guide holes are sequentially arranged in the circumferential direction of the annular turntable at intervals equal to the number of the blades; guide grooves are sequentially arranged in the circumferential direction of the bottom plate at intervals equal to the number of the blades; each of the blades is arranged at the bottom of the inner cylinder and the outer cylinder; the two ends of each blade in the length direction are respectively a wide end and a narrow end, the wide end of which is arranged between the annular turntable and the bottom plate, and guide columns adapted to the guide holes and guide protrusions adapted to the guide grooves are respectively provided on the two side surfaces of the wide end; the narrow end of each blade is arranged in the hollow area between the bottom plate and the shell, and forms a polygonal opening with adjustable opening size along the outer circumference of the column; A linkage rod is provided on the annular turntable, and a through hole for the linkage rod to penetrate and move is provided on the shell; the driving member is provided on the shell, and its output end is connected to the linkage rod for linking the opening and closing of each blade.

2. The powder filling tool according to claim 1, characterized in that: The guide hole includes a waist-shaped hole, one end of which is close to the polygonal opening in the length direction, which is the proximal end, and the other end of which is far away from the polygonal opening in the length direction, which is the distal end; the angle α2 between the line connecting the proximal end of the guide hole and the center of the circumscribed circle of the polygonal opening and the length direction of the guide hole is 50°~80°; the angle α1 between the line connecting the distal end of the guide hole and the center of the circumscribed circle of the polygonal opening and the length direction of the guide hole is 20°~50°.

3. The powder filling tool according to claim 1, characterized in that: One end of the guide groove in the length direction is arranged close to the polygonal opening, which is the proximal end, and the other end of the guide groove in the length direction is arranged away from the polygonal opening, which is the distal end; the angle α3 between the line connecting the proximal end of the guide groove and the center of the circumscribed circle of the polygonal opening and the length direction of the guide groove is 60°~80°; the angle α4 between the line connecting the distal end of the guide groove and the center of the circumscribed circle of the polygonal opening and the length direction of the guide groove is 40°~60°.

4. The powder filling tool according to claim 1, characterized in that: An annular boss is also provided on the outer periphery of the bottom end of the column; the narrow end of each blade is arranged close to or away from the annular boss.

5. The powder filling tool according to claim 1, characterized in that: A circular arc chamfer matched with the core hole of the forming die is provided on the bottom end of the column.

6. The powder filling tool according to claim 1, characterized in that: The number of the blades is 10 to 20; Each of the blades comprises an integrally formed triangular piece and a square piece; an end of the triangular piece away from the square piece is the narrow end, and an end of the square piece away from the triangular piece is the wide end; A circular arc chamfer is provided at the connection between the square piece and the triangular piece; and a circular arc chamfer is provided at one end of the square piece away from the triangular piece.

7. The powder filling tool according to claim 1, characterized in that: A movable gap is set between the blade and the inner cylinder and between the blade and the outer cylinder; the spacing of the movable gap is 0.3~0.5mm.

8. The powder filling tool according to claim 1, characterized in that: The driving member includes a cylinder.

9. A method for using the powder filling tool according to any one of claims 1 to 8, characterized in that: include: Step S1, starting the driving member to drive the linkage rod, thereby sequentially linking the annular turntable and the blades to ensure that the narrow end of each blade is in close contact with the outer circumference of the column to close the bottom of the inner cylinder and the outer cylinder; Filling powder to target heights in the inner and outer annular powder filling areas of the powder filling tool respectively; vibrating the powder filling tool during the powder filling process to ensure that the filled powder is dense; Step S2, opening the upper mold of the forming mold, and inserting the powder-filled tooling into the lower mold core hole of the forming mold with the bottom end of the column positioned; The driving member is activated to drive the linkage rod, which in turn links the annular turntable and the blades in sequence to gradually expand the polygonal opening formed by the narrow ends of the blades, thereby gradually opening the bottoms of the inner cylinder and the outer cylinder. At the same time, the lower mold of the forming mold is controlled to descend along the female mold coaxially arranged outside the lower mold, and the core column coaxial with the lower mold is driven to rise along the core hole. A negative pressure forming cavity is formed by the female mold and the core column, and the powder is filled into the forming cavity by suction. Step S3: After the filling is completed, the powder filling tool is removed, the upper mold is closed, and the upper mold and the lower mold are driven to move toward each other to complete the pressing and forming operation of the powder to form a formed green body product.

10. The method for applying the powder filling tool according to claim 9, characterized in that: The target height is 1.5 to 2 times the height of the formed green body product; the pressure used in the pressing is 150 to 200 MPa; The driving member drives the linkage rod to move at a speed of 20-100 mm / s; The lower die descends at a speed of 20-50 mm / s.

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