Powder forming die for powder metallurgy

Abstract

The invention provides a powder forming die for powder metallurgy, and belongs to the technical field of powder metallurgy, the powder forming die comprises a die holder, a connecting ring, a lining part and a variable pressure unit, and the die holder is provided with a mounting cavity; the inner lining part is arranged in the mounting cavity, the inner lining part and the die holder are arranged at an interval to form a variable pressure cavity, a charging cavity is formed in the side, away from the die holder, of the inner lining part, and the variable pressure cavity and the charging cavity are coaxial; the connecting ring is arranged in the variable pressure cavity and connected to the die holder and the lining piece. The variable pressure unit is arranged in the variable pressure cavity and used for adjusting the air pressure in the variable pressure cavity. The technical problem of defective products caused by stress concentration due to non-uniform distribution of adhesive force during demolding of the blank is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of powder metallurgy, and particularly relates to a powder molding die for powder metallurgy. Background Art

[0002] As an efficient material processing method, metal powder metallurgy technology is widely used in the manufacture of precision parts in industries such as machinery, electronics, and automobiles by pressing metal powders and sintering them into shape. The metal powder molding process relies on a die to apply pressure to the powder, causing loose particles to combine into a dense green body in the die cavity. The die structure directly affects the geometric accuracy and material properties of the parts.

[0003] Currently, in order to facilitate demolding in metal powder metallurgy, a liquid release agent such as zinc stearate or graphite emulsion is sprayed on the surface of the die cavity to assist separation by reducing the friction between the green body and the die.

[0004] However, the release agent is prone to volatilization and failure under high temperature and pressure, and it is difficult to uniformly cover the details of the die cavity, resulting in a sharp increase in local adhesion force. As a result, stress concentration occurs due to uneven adhesion force distribution when the green body is demolded, and thus the green body will appear torn cracks, leading to the production of defective products. Summary of the Invention

[0005] An embodiment of the present invention provides a powder molding die for powder metallurgy, aiming to solve the technical problem that defective products are caused by stress concentration due to uneven adhesion force distribution when the green body is demolded.

[0006] To achieve the above object, the technical solution adopted by the present invention is: to provide a powder molding die for powder metallurgy, including: A die base, provided with an installation cavity; A lining member, disposed in the installation cavity, the lining member is spaced apart from the die base to form a variable pressure cavity, and a loading cavity is provided on a side of the lining member facing away from the die base, and the variable pressure cavity and the loading cavity are coaxial; A connecting ring, disposed in the variable pressure cavity and respectively connected to the die base and the lining member; and A variable pressure unit, disposed in the variable pressure cavity, for adjusting the air pressure in the variable pressure cavity.

[0007] In a possible implementation manner, the variable pressure unit includes: A flow equalizing plate, disposed in the installation cavity, the flow equalizing plate is coaxial with the variable pressure cavity, the flow equalizing plate divides the variable pressure cavity into a flow equalizing cavity and an air cavity from top to bottom, and the flow equalizing plate is provided with flow equalizing holes for communicating the flow equalizing cavity and the air cavity; and An air pump, communicated with the flow equalizing cavity, for adjusting the air pressure in the flow equalizing cavity.

[0008] In a possible implementation, a flow equalizing unit is provided in the flow equalizing cavity, and the flow equalizing unit includes: A spiral blade rotatably connected to the connecting ring; and A first driving member provided on the connecting ring, drivingly connected to the spiral blade, and configured to drive the spiral blade to rotate about the axis of the installation cavity.

[0009] In a possible implementation, the mold base is further provided with a gas source cavity communicating with the flow equalizing cavity, and the flow equalizing unit further includes: A flow equalizing ring covering the opening of the gas source cavity, separating the flow equalizing cavity from the gas source cavity, and rotatably connected to the mold base. The flow equalizing ring is provided with air inlet holes therethrough; and A second driving member provided in the gas source cavity, drivingly connected to the flow equalizing ring, and configured to drive the flow equalizing ring to rotate.

[0010] In a possible implementation, a plurality of annular demolding cavities are provided on the inner circumferential surface of the inner lining member. The plurality of demolding cavities are arranged at intervals in the up and down directions. The opening of the demolding cavity is covered with an inner lining ring. The inner lining ring is coaxial with the loading cavity. The inner wall of the inner lining ring is flush with the inner lining member. The inner lining ring includes a plurality of splicing rings arranged along the axis direction of the loading cavity; The inner lining member is further provided with an avoidance cavity communicating with the demolding cavity. A first telescopic member corresponding to the splicing ring one by one is installed on the inner wall of the avoidance cavity. The first telescopic member telescopically moves in the up and down directions. The movable end of the first telescopic member is fixedly connected with a second telescopic member. The telescopic direction of the second telescopic member is perpendicular to that of the first telescopic member. The movable end of the second telescopic member is fixedly connected with the corresponding splicing ring; and A demolding unit is provided in the demolding cavity, and the demolding unit includes a pressing component and a moving component for driving the pressing component to move up and down; Wherein, when the splicing ring is retracted into the avoidance cavity, the pressing component is activated until it abuts against the outer wall of the blank in the loading cavity, and the moving component moves upward to drive the blank to move upward to complete demolding.

[0011] In a possible implementation, the moving component includes: A moving ring provided in the demolding cavity, and the moving ring is coaxial with the demolding cavity; A screw rod arranged in the up and down direction. A plurality of screw rods are arranged around the circumference of the moving ring. The screw rod is rotatably connected to the inner wall of the demolding cavity around its own central axis direction, and the screw rod is also screwed with the moving ring; and A third driving member provided on the inner wall of the demolding cavity, drivingly connected to the screw rod, and configured to drive the screw rod to rotate.

[0012] In a possible implementation, the pressing component includes: An annular bladder, which is coaxial with the loading cavity and is fixedly connected to the inner circumference of the moving ring; and An inflating member, which is communicated with the annular bladder and is used for inflating and deflating the annular bladder.

[0013] In a possible implementation, the inflating member includes: An air pipe, which is communicated between the annular bladder and the pressure-changing cavity; and An air valve, which is arranged in the air pipe.

[0014] In a possible implementation, a third telescopic member is fixedly connected to the moving ring. The third telescopic member telescopically moves along the radial direction of the moving ring. A plurality of the third telescopic members are arranged around the axis direction of the moving ring. An adsorbing member is fixedly connected to the movable end of the third telescopic member.

[0015] In a possible implementation, two retaining rings are arranged at the opening of the demolding cavity. The two retaining rings are arranged oppositely in the up-and-down direction. One side of each of the two retaining rings away from each other is fixedly connected to the inner wall of the demolding cavity. The inner peripheral surface of the retaining ring is flush with the inner wall of the loading cavity. A retaining groove adapted to the retaining ring is formed in the inner circumference of the splicing ring.

[0016] Compared with the prior art, the powder molding die for powder metallurgy provided by the present invention forms an independent pressure-changing cavity through the nested design of the die base, the connecting ring and the inner lining member, and combines the pressure-changing unit to adjust the air pressure in the pressure-changing cavity. After the metal powder is loaded into the loading cavity, the pressure-changing unit raises the air pressure in the pressure-changing cavity until the air pressure in the pressure-changing cavity is stable, and then maintains the air pressure in the pressure-changing cavity. At this time, the air pressure in the pressure-changing cavity is greater than the air pressure in the loading cavity, and the outer peripheral surface of the inner lining member is extruded, so that the inner wall of the loading cavity is always kept in close contact with the metal powder; after the metal powder is molded in the loading cavity, the pressure-changing unit reduces the air pressure in the pressure-changing cavity until the air pressure in the pressure-changing cavity is less than the air pressure in the loading cavity, and the inner wall of the loading cavity is extruded, so that the inner wall of the loading cavity is separated from the outer peripheral surface of the embryo. The present invention makes the inner wall of the loading cavity close to and separate from the embryo by means of the pressure difference, so that the stress received by the embryo body is uniform both in the molding stage and in the demolding stage, thereby reducing the tearing cracks of the embryo body and further reducing the generation of defective products. Description of the Drawings

[0017] Figure 1 is a cross-sectional view of the powder molding die for powder metallurgy according to an embodiment of the present invention; Figure 2 is a structural schematic diagram of the spiral blade adopted in the embodiment of the present invention; Figure 3 is Figure 1Partial enlarged schematic view of part A; Figure 4 Schematic structural diagram of the demolding unit and the moving mode of the splicing ring adopted in the embodiment of the present invention.

[0018] Explanation of reference numerals: 10. Mold base; 101. Installation cavity; 102. Transformer cavity; 1021. Flow equalizing cavity; 1022. Air cavity; 103. Air source cavity; 20. Connecting ring; 30. Liner; 301. Loading cavity; 302. Demolding cavity; 303. Splicing ring; 3031. Positioning groove; 304. Avoidance cavity; 305. First telescopic member; 3051. Second telescopic member; 306. Positioning ring; 40. Transformer unit; 401. Flow equalizing plate; 4011. Flow equalizing holes; 50. Flow equalizing unit; 501. Spiral blade; 502. First driving member; 5021. First driving gear; 503. Rotating ring; 5031. First driven gear ring; 504. Flow equalizing ring; 5041. Second driven gear ring; 505. Second driving member; 5051. Second driving gear; 60. Demolding unit; 601. Moving ring; 6011. Third telescopic member; 60111. Adsorbing member; 602. Screw; 603. Third driving member; 604. Annular bladder. Specific embodiments

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] Please refer to together Figures 1 to 4 , the powder molding die for powder metallurgy of the present invention will be described. A powder molding die for powder metallurgy includes a mold base 10, a connecting ring 20, a liner 30 and a transformer unit 40. The mold base 10 is provided with an installation cavity 101; the liner 30 is arranged in the installation cavity 101, and the liner 30 is spaced from the mold base 10 to form a transformer cavity 102, and a loading cavity 301 is opened on the side of the liner 30 facing away from the mold base 10, and the transformer cavity 102 and the loading cavity 301 are coaxial; the connecting ring 20 is arranged in the transformer cavity 102 and is respectively connected to the mold base 10 and the liner 30; the transformer unit 40 is arranged in the transformer cavity 102 for adjusting the air pressure in the transformer cavity 102.

[0021] It should be noted that the fixing method of the liner 30 and the connecting ring 20 is detachable connection and fixation. When processing blanks with different diameters, the liner 30 with different inner diameters can be replaced, which improves the application range of the mold.

[0022] Compared with the prior art, the powder molding die for powder metallurgy provided by this embodiment forms an independent variable pressure cavity 102 through the nested design of the die base 10, the connecting ring 20 and the inner lining 30, and combines the variable pressure unit 40 to adjust the air pressure in the variable pressure cavity 102. After loading the metal powder into the loading cavity 301, the variable pressure unit 40 increases the air pressure in the variable pressure cavity 102 until the air pressure in the variable pressure cavity 102 is stable, and then maintains the air pressure in the variable pressure cavity 102. At this time, the air pressure in the variable pressure cavity 102 is greater than the air pressure in the loading cavity 301, and the outer peripheral surface of the inner lining 30 is extruded, so that the inner wall of the loading cavity 301 always keeps in close contact with the metal powder; after the metal powder is formed in the loading cavity 301, the variable pressure unit 40 reduces the air pressure in the variable pressure cavity 102 until the air pressure in the variable pressure cavity 102 is less than the air pressure in the loading cavity 301, and the inner wall of the loading cavity 301 is extruded, so that the inner wall of the loading cavity 301 is separated from the outer peripheral surface of the embryo. The present invention makes the inner wall of the loading cavity 301 close to and separate from the embryo by means of pressure difference, so that the stress received by the embryo body is uniform both in the forming stage and in the demolding stage, thereby reducing the tear-shaped cracks of the embryo body and further reducing the generation of defective products.

[0023] In some embodiments, referring to Figure 1 , the variable pressure unit 40 includes a flow equalizing plate 401 and an air pump; the flow equalizing plate 401 is arranged in the installation cavity 101, the flow equalizing plate 401 and the variable pressure cavity 102 are coaxial, the flow equalizing plate 401 divides the variable pressure cavity 102 into a flow equalizing cavity 1021 and an air cavity 1022 from top to bottom, and the flow equalizing plate 401 is provided with flow equalizing holes 4011 for communicating the flow equalizing cavity 1021 and the air cavity 1022; the air pump is communicated with the flow equalizing cavity 1021 for adjusting the air pressure in the flow equalizing cavity 1021.

[0024] Specifically, a plurality of flow equalizing holes 4011 are arranged at equal intervals along the radial direction of the installation cavity 101 and form a row, and multiple rows of flow equalizing holes 4011 are arranged at equal intervals around the axis direction of the installation cavity 101.

[0025] It should be noted that the gas pumped into the flow equalizing cavity 1021 is an inactive gas, such as helium; the top surface of the metal powder in the loading cavity 301 is lower than the bottom wall of the flow equalizing plate 401.

[0026] When the air pump injects gas into the flow equalizing cavity 1021, the gas needs to enter the air cavity 1022 through the flow equalizing holes 4011. The multiple rows of flow equalizing holes 4011 disperse the gas into multiple thin streams, breaking the limitation of traditional single-point gas supply, avoiding single-direction or local air flow concentration. At the same time, due to the uniform distribution of the flow equalizing holes 4011, the pressure in the air cavity 1022 changes synchronously in the circumferential and radial directions, eliminating the local pressure difference.

[0027] In some embodiments, referring to Figure 1 andFigure 2 Inside the flow equalizing cavity 1021, there is a flow equalizing unit 50. The flow equalizing unit 50 includes a spiral blade 501 and a first driving member 502. The spiral blade 501 is rotatably connected to the connecting ring 20; the first driving member 502 is arranged on the connecting ring 20, is in transmission connection with the spiral blade 501, and is used to drive the spiral blade 501 to rotate with the axis direction of the installation cavity 101 as the rotation axis.

[0028] Specifically, the flow equalizing unit 50 further includes a rotating ring 503. The rotating ring 503 is arranged inside the flow equalizing cavity 1021. The rotating ring 503 is coaxial with the flow equalizing cavity 1021. The top wall of the rotating ring 503 is fixedly connected with a first driven gear ring 5031 coaxial with itself. The top end of the spiral blade 501 is fixedly connected with the bottom wall of the rotating ring 503; the first driving member 502 can be a motor. The first driving member 502 is installed on the bottom wall of the connecting ring 20. The output shaft of the first driving member 502 is fixedly connected with a first driving gear 5021 meshing with the first driven gear ring 5031.

[0029] It should be noted that when the pressure in the pressure conversion cavity 102 rises and falls, the rotation direction of the output shaft of the first driving member 502 is opposite.

[0030] When the first driving member 502 starts, it drives the first driving gear 5021 to rotate. The first driving gear 5021 drives the first driven gear ring 5031 to rotate. Thus, the gear ring drives the rotating ring 503 to rotate, and the rotating ring 503 drives the spiral blade 501 to rotate.

[0031] When the air pump injects gas into the flow equalizing cavity 1021, the initial air flow is likely to form local eddies or stagnant areas. The rotating spiral blade 501 cuts the large-scale eddies into tiny vortices, reducing the turbulence intensity. The gas is forced to move regularly inside the flow equalizing cavity 1021. When the pressure in the pressure conversion cavity 102 rises, the gas accelerates downward, improving the pressure rising efficiency; when the pressure in the pressure conversion cavity 102 falls, the gas accelerates upward, improving the pressure falling efficiency.

[0032] In some embodiments, referring to Figure 1 , the mold base 10 further has an air source cavity 103 communicating with the flow equalizing cavity 1021. The flow equalizing unit 50 further includes a flow equalizing ring 504 and a second driving member 505; the flow equalizing ring 504 covers the opening of the air source cavity 103, separates the flow equalizing cavity 1021 from the air source cavity 103, and is rotatably connected to the mold base 103. The flow equalizing ring 504 is provided with air inlet holes in a penetrating manner; the second driving member 505 is arranged inside the air source cavity 103, is in transmission connection with the flow equalizing ring 504, and is used to drive the flow equalizing ring 504 to rotate.

[0033] Specifically, the second driving member 505 is a motor. The output shaft of the second driving member 505 is fixedly connected with a second driving gear 5051. The inner peripheral surface or the outer peripheral surface of the flow equalizing ring 504 is fixedly connected with a second driven gear ring 5041 meshing with the second driving gear 5051.

[0034] Specifically, a plurality of air inlets are uniformly spaced along the axial direction of the flow equalizing ring 504.

[0035] It should be noted that the structure in the figure is.

[0036] The second driving member 505 starts to drive the second driving gear 5051 to rotate. The rotation of the second driving gear 5051 drives the second driven gear ring 5041 to rotate. The rotation of the second driven gear ring 5041 drives the flow equalizing ring 504 to rotate. During the rotation of the flow equalizing ring 504, the circumferential position of the air inlets is continuously changed, thereby continuously adjusting the position points where the gas enters the flow equalizing cavity 1021, so as to make the gas in the flow equalizing cavity 1021 evenly distributed.

[0037] In some embodiments, referring to Figure 1 and Figure 4 , a plurality of annular demolding cavities 302 are formed on the inner circumferential surface of the inner lining member 30. The plurality of demolding cavities 302 are spaced at intervals in the up and down direction. The opening of the demolding cavity 302 is covered with an inner lining ring. The inner lining ring is coaxial with the loading cavity 301. The inner wall of the inner lining ring is flush with the inner lining member 30. The inner lining ring includes a plurality of splicing rings 303 arranged along the axial direction of the loading cavity 301. The inner lining member 30 is also provided with an avoidance cavity 304 communicating with the demolding cavity 302. A first telescopic member 305 corresponding to the splicing ring 303 one by one is installed on the inner wall of the avoidance cavity 304. The first telescopic member 305 telescopes in the up and down direction. The movable end of the first telescopic member 305 is fixedly connected with a second telescopic member 3051. The telescopic direction of the second telescopic member 3051 is perpendicular to that of the first telescopic member 305. The movable end of the second telescopic member 3051 is fixedly connected with the corresponding splicing ring 303. A demolding unit 60 is arranged in the demolding cavity 302. The demolding unit 60 includes a pressing component and a moving component for driving the pressing component to move up and down.

[0038] Wherein, after the splicing ring 303 is retracted into the avoidance cavity 304, the pressing component is activated until it abuts against the outer wall of the blank in the loading cavity 301. The moving component is activated to move upward to drive the blank to move upward, completing demolding.

[0039] Specifically, both the first telescopic member 305 and the second telescopic member 3051 can be telescopic oil cylinders, hydraulic cylinders, or electric cylinders.

[0040] After the metal powder is formed in the loading cavity 301, the second telescopic member 3051 is activated to retract, driving the splicing ring 303 to move into the demolding cavity 302. Until the splicing ring 303 is aligned with the avoidance cavity 304, the first telescopic member 305 is activated to retract, driving the splicing ring 303 to move upward until the splicing ring 303 is retracted into the avoidance cavity 304. After the splicing ring 303 is retracted into the avoidance cavity 304, the pressing component starts to be activated to press against the outer peripheral surface of the blank, and then the moving component drives the blank to move upward, thereby completing demolding.

[0041] The combined design of the demoulding cavity 302 and the splicing ring 303 controls the splicing ring 303 to be retracted into the avoidance cavity 304 through the first telescopic part 305 and the second telescopic part 3051, so that the lining part 30 is partially separated from the embryo during demoulding, reducing the demoulding resistance; the cooperation of the clamping component and the moving component can stably drive the embryo to move upward, avoiding surface damage caused by friction during the demoulding process.

[0042] In some embodiments, see Figure 4 The moving assembly includes a moving ring 601, a screw 602 and a third driving member 603. The moving ring 601 is arranged in the demolding cavity 302, and the moving ring 601 is coaxial with the demolding cavity 302; the screw 602 is arranged in the up and down directions, and multiple screws 602 are arranged around the circumference of the moving ring 601. The screw 602 is rotatably connected to the inner wall of the demolding cavity 302 around its own central axis direction, and the screw 602 is also screwed to the moving ring 601; the third driving member 603 is arranged on the inner wall of the demolding cavity 302, and is transmission-connected to the screw 602, and is used to drive the screw 602 to rotate.

[0043] Specifically, the third driving member 603 corresponds to the screw rod 602 one by one. The third driving member 603 is a motor. The output shaft of the third driving member 603 is directly fixed to the center of the end surface of the screw rod 602 .

[0044] The third driving member 603 starts to drive the screw 602 to rotate, so that the screw 602 drives the moving ring 601 to move upward. During the upward movement of the moving ring 601, the synchronous rotation of multiple screws 602 ensures the smooth lifting of the moving ring 601, so that the moving ring 601 can smoothly drive the embryo to move upward through the clamping assembly to avoid tilting or jamming of the embryo caused by unbalanced load; the rotation direction of the screw 602 can be changed by changing the rotation of the output shaft of the third driving member 603, so that the screw 602 drives the moving ring 601 to move downward and reset.

[0045] In some embodiments, the moving component is a fourth telescopic member, which is telescopic in the up and down directions. The fourth telescopic member can be a telescopic oil cylinder, a hydraulic cylinder, or an electric cylinder. The moving ring 601 can be moved up and down by extending and retracting the fourth telescopic member.

[0046] The multi-screw 602 can achieve strictly synchronous movement through thread transmission, and the self-locking feature of the thread can prevent the movable ring 601 from shifting due to gravity or vibration; the piston rod of the fourth telescopic part is prone to elastic deformation under continuous high pressure, affecting the demolding stability. At the same time, the piston rod of the fourth telescopic part is prone to bend and deform when subjected to radial force, and long-term use can easily cause wear and leakage of the seal.

[0047] In some embodiments, see Figure 4, the pressing component includes an annular bladder 604 and an inflating member (not shown). The annular bladder 604 is coaxial with the loading cavity 301, and the annular bladder 604 is fixedly connected to the inner circumference of the moving ring 601; the inflating member is in communication with the annular bladder 604 and is used to inflate and deflate the annular bladder 604.

[0048] After the annular bladder 604 is inflated, it uniformly fits against the outer wall of the embryo, and the pressing force is dispersed through flexible contact to prevent hard contact from scratching the surface of the embryo. In some embodiments, the pressing component is a fifth telescopic member, and the fifth telescopic member telescopically moves along the radial direction of the loading cavity 301. The fifth telescopic member can be a telescopic oil cylinder, a hydraulic cylinder, or an electric cylinder.

[0049] The contact between the fifth telescopic member and the outer wall of the embryo is hard contact, which is likely to damage the outer wall of the embryo.

[0050] In some embodiments, the inflating member includes an air pipe and an air valve. The air pipe is in communication with the annular bladder 604 and the pressure-changing cavity 102; the air valve is provided in the air pipe.

[0051] The annular bladder 604 is communicated with the pressure-changing cavity 102 through the air pipe, and the existing air pressure resources of the pressure-changing cavity 102 are used to supply air to the annular bladder 604, eliminating the need for an independent air source device, simplifying the structure and reducing costs.

[0052] In some embodiments, the inflating member is an air pump, and an external air pump is added to supply air to the annular bladder 604, increasing the air supply cost.

[0053] In some embodiments, refer to Figure 4 , a third telescopic member 6011 is fixedly connected to the moving ring 601. The third telescopic member 6011 telescopically moves along the radial direction of the moving ring 601. A plurality of third telescopic members 6011 are arranged around the axis of the moving ring 601, and an adsorbing member 60111 is fixedly connected to the movable end of the third telescopic member 6011.

[0054] Specifically, the adsorbing member 60111 is an electric vacuum suction cup. The adsorbing member 60111 generates suction force when powered on and adsorbs and fixes to the annular bladder 604, and the suction force disappears and it separates from the annular bladder 604 when the adsorbing member 60111 is powered off.

[0055] After the splicing ring 303 is put into the storage cavity, the third telescopic part 6011 extends out to drive the adsorption part 60111 to extend out. When the adsorption part 60111 is energized, the adsorption part 60111 and the side of the annular bag 604 away from the moving ring 601 are adsorbed and fixed, and then the third telescopic part 6011 continues to extend to drive the annular bag 604 to extend out of the demolding cavity 302. After the third telescopic part 6011 is retracted and reset, the annular bag 604 begins to inflate; after the annular bag 604 is deflated, the third telescopic part 6011 extends out to drive the adsorption part 60111 to extend out. When the adsorption part 60111 is energized, the adsorption part 60111 and the side of the annular bag 604 away from the moving ring 601 are adsorbed and fixed, and then the third telescopic part 6011 is retracted and drives the annular bag 604 to be put into the demolding groove through the adsorption part 60111. The adsorption part 60111 is powered off and separated from the annular bag 604, thereby ensuring that the annular bag 604 is put into the demolding cavity 302.

[0056] In some embodiments, see Figure 3 Two shifting rings 306 are provided at the opening of the demoulding cavity 302. The two shifting rings 306 are arranged opposite to each other in the up and down directions. The two shifting rings 306 are fixedly connected to the inner wall of the demoulding cavity 302 on the sides away from each other. The inner circumference of the shifting ring 306 is flush with the inner wall of the loading cavity 301. The inner circumference of the splicing ring 303 is provided with a shifting groove 3031 adapted to the shifting ring 306.

[0057] The matching design of the shift ring 306 and the shift groove 3031 ensures that the splicing ring 303 is accurately positioned in the closed state, thereby avoiding poor sealing of the charging chamber 301 or powder leakage due to splicing misalignment.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A powder forming die for powder metallurgy, characterized in that: include: The mold base is provided with a mounting cavity; An inner lining member is arranged in the installation cavity, the inner lining member is spaced apart from the mold base to form a variable pressure cavity, and a loading cavity is provided on a side of the inner lining member away from the mold base, and the variable pressure cavity and the loading cavity are coaxial; A connecting ring is disposed in the pressure changing chamber and is respectively connected to the mold base and the lining member; as well as The transformer unit is arranged in the transformer chamber and is used for adjusting the air pressure in the transformer chamber.

2. The powder forming die for powder metallurgy according to claim 1, characterized in that: The transformer unit comprises: a flow balancing plate, arranged in the installation cavity, the flow balancing plate and the transformer cavity being coaxial, the flow balancing plate dividing the transformer cavity from top to bottom into a flow balancing cavity and an air cavity, the flow balancing plate being provided with a flow balancing hole connecting the flow balancing cavity and the air cavity; and An air pump is connected to the flow balancing chamber and is used to adjust the air pressure in the flow balancing chamber.

3. The powder forming die for powder metallurgy according to claim 2, characterized in that: A flow balancing unit is provided in the flow balancing cavity, and the flow balancing unit includes: a spiral blade, rotatably connected to the connecting ring; and The first driving member is arranged on the connecting ring, is drivingly connected to the spiral blade, and is used for driving the spiral blade to rotate with the axial direction of the installation cavity as the rotation axis.

4. The powder forming die for powder metallurgy according to claim 3, characterized in that: The mold base is also provided with an air source cavity connected to the flow balancing cavity, and the flow balancing unit further comprises: A flow-equalizing ring, covering the opening of the gas source cavity, separating the flow-equalizing cavity from the gas source cavity, and rotatably connected to the mold base, wherein the flow-equalizing ring is penetrated by an air inlet hole; and The second driving member is disposed in the gas source cavity and is drivingly connected to the flow balancing ring to drive the flow balancing ring to rotate.

5. The powder forming die for powder metallurgy according to claim 1, characterized in that: The inner circumferential surface of the lining member is provided with a plurality of annular demoulding cavities, the plurality of demoulding cavities are arranged at intervals in the up-down direction, the opening of the demoulding cavity is covered with an inner lining ring, the inner lining ring is coaxial with the charging cavity, the inner wall of the inner lining ring is flush with the lining member, and the inner lining ring includes a plurality of splicing rings arranged around the axial direction of the charging cavity; The lining member is further provided with an avoidance cavity connected to the demoulding cavity, and the inner wall of the avoidance cavity is provided with a first telescopic member corresponding to the splicing ring one by one, the first telescopic member is telescopic in the up-down direction, the movable end of the first telescopic member is fixedly connected to the second telescopic member, the telescopic direction of the second telescopic member is perpendicular to the first telescopic member, and the movable end of the second telescopic member is fixedly connected to the corresponding splicing ring; and A demoulding unit is provided in the demoulding cavity, and the demoulding unit includes a clamping component and a moving component for driving the clamping component to move up and down; Among them, when the splicing ring is received into the avoidance cavity, the pressing component is started until it is pressed against the outer wall of the embryo body in the loading cavity, and the moving component moves upward to drive the embryo body to move upward, thereby completing demoulding.

6. The powder forming die for powder metallurgy according to claim 5, characterized in that: The mobile assembly comprises: A moving ring is arranged in the demoulding cavity, and the moving ring is coaxial with the demoulding cavity; A screw rod is arranged in the up-down direction, a plurality of the screw rods are arranged around the circumference of the moving ring, the screw rod is rotatably connected to the inner wall of the demoulding cavity around its own central axis, and the screw rod is also threadedly connected to the moving ring; and The third driving member is arranged on the inner wall of the demoulding cavity and is drivingly connected to the screw rod to drive the screw rod to rotate.

7. The powder forming die for powder metallurgy according to claim 6, characterized in that: The tightening assembly comprises: an annular bladder bag, the annular bladder bag is coaxial with the charging cavity, and the annular bladder bag is fixedly connected to the inner circumference of the moving ring; and An inflatable member is communicated with the annular bladder and is used for inflating and deflating the annular bladder.

8. The powder forming die for powder metallurgy according to claim 7, characterized in that: The inflatable member comprises: an airway connected to the annular bag and the pressure-changing chamber; and The air valve is arranged in the air pipe.

9. The powder forming die for powder metallurgy according to claim 7, characterized in that: A third telescopic member is fixedly connected to the moving ring. The third telescopic member is telescopic in the radial direction of the moving ring. A plurality of third telescopic members are arranged around the axis of the moving ring. An adsorption member is fixedly connected to the movable end of the third telescopic member.

10. The powder forming die for powder metallurgy according to claim 5, characterized in that: Two shifting rings are provided at the opening of the demoulding cavity, and the two shifting rings are arranged opposite to each other in the up and down directions. The two shifting rings are fixedly connected to the inner wall of the demoulding cavity on the sides away from each other, and the inner circumference of the shifting ring is flush with the inner wall of the loading cavity. The inner circumference of the splicing ring is provided with a shifting groove adapted to the shifting ring.

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