Powder metallurgy mold with reduced demolding force

Abstract

The application discloses a powder metallurgy mold capable of reducing demolding force, comprising a mold sleeve, a mold core cavity provided in the mold sleeve, an inner side wall of the mold core cavity being provided with a first guide part, a mold core assembly comprising at least two mold cores and an elastic part, the at least two mold cores being inserted into the mold core cavity, inner side walls of the at least two mold cores jointly surrounding a forming cavity, an outer side wall of the mold core being provided with a second guide part, the elastic part being used for providing an elastic stress, the elastic stress driving the at least two mold cores to move downward, the second guide part being used for slidingly matching with the first guide part, the first guide part being used for guiding the at least two mold cores to move close to each other when the second guide part moves downward, so that the at least two mold cores are in a first state, and the first guide part being used for guiding the at least two mold cores to move away from each other when the second guide part moves upward, so that the at least two mold cores are in a second state. The at least two mold cores can slide upward along the mold core cavity and open when demolding, so that the product in the forming cavity can be smoothly demolded.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy fixture technology, and in particular to a powder metallurgy mold that reduces demolding force. Background Technology

[0002] Currently, powder metallurgy is a process technology that produces metal powder or uses metal powder as raw material, and then manufactures metal materials, composite materials and various types of products through forming and sintering. Therefore, during manufacturing, the material powder is first filled between the molds, and then compacted and heated through the molds to finally obtain the finished product.

[0003] When the product is slender (total length exceeding 45mm), since the product is formed by powder compaction, if the ejection force is too large during demolding, and the friction between the product and the mold cavity is large, the length of the product will decrease during the ejection process due to the interaction of the upward ejection force and the downward friction between the product and the inner wall of the mold cavity. This results in poor product molding accuracy or even direct product damage. Summary of the Invention

[0004] In order to overcome at least one of the defects of the prior art, the present invention provides a powder metallurgy mold that reduces demolding force, wherein at least two mold cores can slide upward and open along the mold core cavity during demolding, so as to facilitate the smooth release of the product in the molding cavity.

[0005] The technical solution adopted by this invention to solve its problem is: A powder metallurgical mold for reducing release force, comprising, A mold sleeve, wherein the mold sleeve is provided with a mold core cavity, and the inner sidewall of the mold core cavity is provided with a first guide portion; A mold core assembly includes at least two mold cores and an elastic member. The at least two mold cores pass through a mold core cavity and slide against the inner wall of the cavity. The inner walls of the at least two mold cores together form a molding cavity. A second guide portion is provided on the outer wall of each mold core. The elastic member is located between the mold sleeve and the mold core. The elastic member provides an elastic stress that drives the at least two mold cores downward. The second guide portion slides against the first guide portion. When the second guide portion moves downward, the first guide portion guides the at least two mold cores closer together to each other, so that the at least two mold cores are in a first state. When the second guide portion moves upward, the first guide portion guides the at least two mold cores further apart to each other, so that the at least two mold cores are in a second state.

[0006] Furthermore, the top of the mold core has a mold core segment extending out of the mold core cavity, and the outer wall of the mold core segment is provided with an abutment step; the elastic member abuts against the abutment step and is used to provide an elastic stress applied to the abutment step to drive the mold core to move downward.

[0007] Furthermore, the elastic component includes an elastic pad; the elastic pad is fitted over the core segments of at least two of the cores and abuts against the abutment step.

[0008] Furthermore, the powder metallurgy mold also includes a pressure cap, which is connected to the top of the mold sleeve and fitted over the mold core segments of at least two of the mold cores to press against the elastic pad.

[0009] Furthermore, the inner peripheral wall of the bottom end of the cover is provided with a pressing step, and the elastic pad is sandwiched between the pressing step and the abutting step.

[0010] Furthermore, the pressure cap has a plurality of first connecting holes in its circumferential direction, and the top of the mold sleeve has a plurality of second connecting holes; the plurality of first connecting holes and the plurality of second connecting holes correspond one-to-one, and connecting members are inserted into the first connecting holes and the second connecting holes so that the pressure cap is connected to the mold sleeve.

[0011] Furthermore, the inner wall of the mold core cavity is provided with a first conical surface, which gradually slopes outward from bottom to top; the first conical surface is formed as the first guide portion.

[0012] Furthermore, the outer wall of the mold core is provided with a second conical surface, which gradually slopes outward from bottom to top, and the second conical surface slides in fit with the first conical surface; the second conical surface is formed as the second guide portion.

[0013] Furthermore, there are four mold cores, which together form the molding cavity.

[0014] Furthermore, the powder metallurgy mold further includes an upper punch, a first lower punch, and a second lower punch. The upper punch moves from top to bottom towards the top of the mold core. The first lower punch passes through the mold core and can move from bottom to top towards or away from the bottom of the mold core. One end of the second lower punch is formed into a forming section. The bottom end of the second lower punch passes through the first lower punch and can move up and down along the mold core to drive the forming section to move up and down. The outer peripheral wall of the forming section cooperates with the inner sidewall of the mold core to form the forming cavity.

[0015] In summary, the present invention has the following technical effects: When the product is demolded, as it is ejected upwards, the elastic components cause the mold core to move upwards along with it due to friction. The second guide part of the mold core can then slide and engage with the first guide part. At this time, the first guide part can guide the upward-moving mold core to move outwards simultaneously, so that at least two mold cores can move away from each other. After the elastic components are compressed to a certain extent, the mold cores stop moving upwards. Since the mold cores are now separated and open, the product can detach from the molding cavities of the open mold cores. The product will not be obstructed by friction during demolding, so the product length will not decrease during demolding, and the product precision will be higher after demolding. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is an exploded structural diagram of the present invention; Figure 3 This is a partial structural diagram of the present invention; Figure 4 This is a schematic diagram of the core assembly of the present invention.

[0017] The meanings of the reference numerals in the attached drawings are as follows: 10, mold sleeve; 11, mold core cavity; 12, second connecting hole; 20, mold core; 21, mold core section; 22, abutting step; 30, elastic component; 40, pressure cap; 41, first connecting hole; 50, first punch; 60, second punch; 61, forming section; 70, upper punch; 80, forming cavity; 90, product. Detailed Implementation

[0018] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0019] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0021] See Figures 1-4 This invention discloses a powder metallurgy mold for reducing demolding force, comprising a mold sleeve 10 and a mold core 20 assembly. A mold core cavity 11 is provided within the mold sleeve 10, and a first guide portion is provided on the inner sidewall of the mold core cavity 11. The aforementioned mold core 20 assembly includes at least two mold cores 20 and an elastic member 30. The at least two mold cores 20 pass through the mold core cavity 11, and the outer sidewall of the mold core 20 slides in fit with the inner sidewall of the mold core cavity 11. The inner sidewalls of the at least two mold cores together form a molding cavity 80, and a second guide portion is provided on the outer sidewall of the mold core 20.

[0022] An elastic member 30 is disposed between the mold sleeve 10 and the mold core 20. The elastic member 30 provides an elastic stress that drives at least two mold cores 20 to move downwards and maintains a tendency to extend into the mold core cavity 11. Specifically, the first guide portion can slide into the second guide portion when the second guide portion moves downwards, thereby guiding at least two mold cores 20 closer together to achieve a first state. Conversely, when the second guide portion moves upwards, the first guide portion guides at least two mold cores 20 further apart to achieve a second state.

[0023] Based on the above structure, using the powder metallurgy mold of the present invention that reduces demolding force, when molding product 90, at least two mold cores 20 move downward and extend into the mold core cavity 11 of the mold sleeve 10. During the downward movement, the second guide portion of the outer wall of the mold core 20 slides and engages with the first guide portion of the mold core cavity 11. Under the guidance of the first guide portion, at least two mold cores 20 maintain a first state of being close to each other. When at least two mold cores 20 are close to each other, at least two mold cores 20 form a closed enclosure state in the circumferential direction of the mold core cavity 11. Therefore, the formed molding cavity 80 is circumferentially closed, and powder leakage will not occur during the powder compaction molding process.

[0024] Furthermore, under the elastic stress provided by the elastic member 30, at least two mold cores 20 tend to move downwards. Thus, at least two mold cores 20 can maintain the first state of extending into the mold core cavity 11 and approaching each other. That is, the molding cavity 80 formed by at least two mold cores 20 can remain closed and enclosed, preventing cracks in the formed molding cavity 80 and causing powder leakage, thereby improving molding accuracy.

[0025] Of course, after product 90 is compacted and molded, it needs to be demolded. At this time, by pressing the bottom end of product 90 upwards, product 90 can be ejected upwards from the molding cavity 80. During the upward demolding process of product 90, there will be a certain friction between the outer wall of product 90 and the inner wall of the molding cavity 80 formed by the mold core 20. If product 90 is ejected upwards directly, the friction between the mold and product 90 will be greater than the upward ejection force, which will cause the length of the powder-pressed product 90 to become shorter during this process, and demolding will be stuck, affecting the accuracy of product 90.

[0026] Therefore, in this application, when the product 90 is demolded, as the product 90 is ejected upwards, due to the setting of the elastic component 30, the product 90 moves upwards and, due to the friction, will bring the mold core 20 upwards with it. The second guide part of the mold core 20 can then slide and engage with the first guide part. At this time, the first guide part can guide the upwardly moving mold core 20 to move outwards simultaneously. In this way, at least two mold cores 20 can move away from each other. After the elastic component 30 is compressed to a certain extent, the mold core 20 no longer moves upwards. At this time, since each mold core 20 moves away from each other and opens up, the product 90 can disengage from the molding cavity 80 of each opened mold core 20. The product 90 will not be obstructed from demolding due to the friction. Therefore, the length of the product 90 will not become shorter during the demolding process, and the product 90 will have higher precision after demolding.

[0027] Furthermore, in this embodiment, the top of the mold core 20 has a mold core segment 21 extending out of the mold core cavity 11. Specifically, an abutment step 22 is provided on the outer wall of the mold core segment 21. The aforementioned elastic member 30 abuts against the abutment step 22, and the elastic member 30 can provide elastic stress applied to the abutment step 22 to drive the mold core 20 to move downward. Based on this structure, when assembling the mold core 20 assembly, at least two mold cores 20 extend into the mold core cavity 11, and the mold core segment 21 at the top of each mold core 20 extends out of the mold core cavity 11. The elastic member 30 applies force to the abutment step 22 of each mold core segment 21 so that the abutment step 22 bears the elastic stress applied by the elastic member 30. In this way, the force application surface of the elastic member 30 is stable, the mold core 20 is subjected to uniform force, and the swaying of the mold core 20 when moving upward is reduced.

[0028] More specifically, the aforementioned elastic component 30 includes an elastic pad, which is fitted around the core segments 21 of at least two cores 20. Since the elastic pad is fitted onto and abuts against the abutment steps 22 of each core 20 in the circumferential direction, the elastic pad can simultaneously apply force to the abutment steps 22 of each core 20, and the force applied at each position of the elastic pad is the same. Thus, when the elastic pad provides elastic stress to drive each core 20 downwards, the elastic pad can simultaneously apply the same magnitude of elastic stress to the core segments 21 in the circumferential direction. Each core 20 remains synchronously downwards and moves closer to each other under the action of the first and second guides. At this time, the elastic pad fitted around each core segment 21 can also be radially reset, gripping each core segment 21, so that each core 20 can maintain a stable closed enclosure state. Therefore, the formed molding cavity 80 is circumferentially closed, effectively preventing powder leakage during molding.

[0029] However, during demolding, as each mold core 20 moves upward and opens outward, the elastic pad will be compressed axially. At the same time, as each part opens outward, the mold core segment 21 can also radially compress the elastic pad, so that the elastic pad can be compressed radially. That is, by using the elastic pad to fit the mold core segment 21 and abut against the abutment step 22, both radial elastic stress and axial elastic stress can be provided, which facilitates the application of radial and axial forces to the mold core 20.

[0030] Furthermore, the powder metallurgy mold in this embodiment also includes a pressure cap 40, which is connected to the top of the mold sleeve 10 and fitted over the mold core segments 21 of at least two mold cores 20 to press against the elastic rubber pad. Thus, when assembling at least two mold cores 20 of the mold core 20 assembly, at least two mold cores 20 extend into the mold core cavity 11, while the mold core segments 21 extend out of the mold core cavity 11. After the elastic rubber pad is fitted onto each mold core segment 21, it is then pressed tightly onto the elastic rubber pad by the pressure cap 40. The gap created after the pressure cap 40 and the mold sleeve 10 are assembled provides space for the elastic rubber pad to expand and contract, and the pressure cap 40 limits the position above the elastic rubber pad, making the assembly structure more stable.

[0031] At that time, the aforementioned elastic pad was a rubber pad or a silicone pad. In other cases, the aforementioned elastic component 30 can also be implemented using a spring structure, and it can also be implemented by having multiple springs distributed circumferentially upward on the pressure cap 40 apply force to the abutment steps 22 of each mold core segment 21 respectively.

[0032] Furthermore, the bottom inner peripheral wall of the aforementioned pressure cap 40 is provided with a pressing step, which clamps the elastic pad between the pressing step and the abutment step 22. After the pressure cap 40 is assembled to the top of the mold sleeve 10, the pressure cap 40 is fitted onto the outside of each mold core segment 21. In this way, a space is formed between the pressing step and the abutment step 22 for the elastic pad to be assembled and expand and contract. The abutment step 22 and the pressing step can limit the elastic pad in the axial direction, while the outer wall of the mold core segment 21 and the inner peripheral wall of the pressure cap 40 limit the elastic pad in the radial direction. The reset and compression of the elastic pad are more stable.

[0033] Furthermore, to facilitate the assembly of the pressure cap 40, multiple first connecting holes 41 are provided on the circumference of the pressure cap 40, and multiple second connecting holes 12 are provided on the top of the mold sleeve 10. When assembling the pressure cap 40 and the mold sleeve 10, the multiple first connecting holes 41 on the pressure cap 40 correspond one-to-one with the multiple second connecting holes 12 on the mold sleeve 10. Then, connectors are inserted into the first connecting holes 41 and the second connecting holes 12 to connect the pressure cap 40 to the mold sleeve 10. The pressure cap 40 and the mold sleeve 10 are assembled by multiple connectors evenly distributed in the circumference. The connectors are evenly distributed, and the pressure cap 40 is subjected to uniform force at all positions in the circumference. The elastic rubber gasket set between the pressure cap 40 and the mold sleeve 10 can also be subjected to uniform force.

[0034] Of course, in this embodiment, bolts can be used as the connecting parts. The first connecting hole 41 and the second connecting hole 12 are threaded holes. The bolts connect the first connecting hole 41 and the second connecting hole 12. After the pressure cap 40 is assembled into the mold sleeve 10, the clamping force of the pressure cap 40 on the elastic pad can be adjusted by rotating the bolt. That is, the elastic stress provided by the elastic pad can be adjusted accordingly. When the bolt is screwed into the second connecting hole 12 to a deep depth, the pressure cap 40 is close to the mold sleeve 10 and pressed against the elastic pad. At this time, the elastic pad is in a compressed state and provides greater elastic stress. When the bolt is screwed into the second connecting hole 12 to a shallow depth, the gap between the pressure cap 40 and the mold sleeve 10 is larger, and the elastic pad is more easily compressed and more easily deformed by the mold core 20.

[0035] Furthermore, the inner wall of the mold core cavity 11 is provided with a first conical surface, which gradually slopes outward from bottom to top. The first conical surface forms a first guide portion, so that when the second guide portion of the mold core 20 moves upward along the first conical surface, the first conical surface slopes outward from bottom to top, thus guiding the mold core 20 to move outward, and the individual mold cores 20 can move away from each other and open up. Of course, when the mold core 20 moves downward, when the second guide portion moves downward along the first conical surface, the first conical surface slopes outward from bottom to top, thus guiding the mold core 20 to move inward, and the individual mold cores 20 can move closer to each other and tighten up.

[0036] More specifically, the outer wall of the aforementioned mold core 20 is provided with a second conical surface. The second conical surface gradually slopes outward from bottom to top, and the second conical surface slides in conjunction with the first conical surface, forming a second guide portion. In this way, when the mold core 20 moves up and down, it can slide in conjunction with the first conical surface, making the movement of the mold core 20 smoother and reducing jamming.

[0037] Of course, the second guide part can also be formed by an arc protrusion structure or a wedge block protruding from the outer wall of the mold core 20, as long as it can slide and cooperate with the first conical surface to achieve guidance.

[0038] It should also be noted that the first and second guide parts mentioned above can also be implemented as inclined plane structures. In short, any structure that can guide the radial movement of the mold core 20 when sliding up and down is acceptable.

[0039] Furthermore, there are four mold cores 20, which together form a molding cavity. In this way, the mold core 20 assembly opens and closes with four mold cores 20, which is easier to open than with two or three mold cores 20.

[0040] Furthermore, the powder metallurgy mold also includes an upper punch 70, a first lower punch, and a second lower punch. The upper punch 70 moves from top to bottom towards the top of the mold core. The first lower punch passes through the mold core and can move from bottom to top towards or away from the bottom of the mold core. One end of the second lower punch is formed into a forming section 61. The bottom end of the second lower punch passes through the first lower punch and can move up and down along the mold core to drive the forming section 61 to move up and down. The outer peripheral wall of the forming section 61 cooperates with the inner side wall of the mold core to form a forming cavity 80.

[0041] When molding product 90, at least two mold cores 20 can be placed into the mold core cavity 11. Then, the first lower punch moves upward and extends into the bottom end of the mold core. Then, the second lower punch moves upward, and the forming section 61 of the second lower punch passes through the first lower punch and exits into the mold core. The outer wall of the forming section 61 and the inner wall of the mold core 20 are spaced apart to form the aforementioned forming cavity 80. Powder is then placed into the forming cavity 80, and the upper punch 70 moves downward to press the powder, thus forming the corresponding product 90 structure. During demolding, the upper punch 70 moves upward and exits the forming cavity 80, and then the first lower punch pushes upward to form product 90.

[0042] Of course, a stepped structure can be set on the forming section 61 of the second lower punch, and a toothed groove structure can be set on the outer peripheral wall of the upper punch 70. In this way, the toothed groove structure can be formed on the product 90 in the forming cavity 80 by pressing down with the upper punch 70. At the same time, the step of the forming section 61 and the top pressure of the upper punch 70 can form the stepped structure on the product 90. By using different punch structures to form the forming cavity 80 and forming toothed grooves, steps and other structures, the product 90 can be separated and exited from the forming cavity 80 during demolding, making demolding more convenient and less likely to be damaged.

[0043] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A powder metallurgy mold for reducing demolding force, characterized in that, include, A mold sleeve, wherein the mold sleeve is provided with a mold core cavity, and the inner sidewall of the mold core cavity is provided with a first guide portion; A mold core assembly includes at least two mold cores and an elastic member. The at least two mold cores pass through a mold core cavity and slide against the inner sidewall of the cavity. The inner sidewalls of the at least two mold cores together form a molding cavity. A second guide portion is provided on the outer sidewall of each mold core. The elastic member is located between the mold sleeve and the mold cores. The elastic member provides an elastic stress that drives the at least two mold cores downward. The second guide portion slides against the first guide portion. When the second guide portion moves downward, the first guide portion guides the at least two mold cores closer together to a first state. When the second guide portion moves upward, the first guide portion guides the at least two mold cores further apart to a second state. The top of the mold core has a mold core section extending out of the mold core cavity, and the outer wall of the mold core section is provided with an abutment step; the elastic member abuts against the abutment step and is used to provide an elastic stress applied to the abutment step to drive the mold core to move downward; The powder metallurgy mold further includes a pressure cap, which is connected to the top of the mold sleeve and fitted over the mold core segments of at least two of the mold cores to press against the elastic member.

2. The powder metallurgy mold for reducing demolding force according to claim 1, characterized in that, The elastic component includes an elastic pad; the elastic pad is fitted over the mold core segments of at least two of the mold cores and abuts against the abutment step.

3. The powder metallurgy mold for reducing demolding force according to claim 2, characterized in that, The inner peripheral wall of the bottom end of the pressure cap is provided with a pressing step, and the elastic pad is sandwiched between the pressing step and the abutting step.

4. The powder metallurgy mold for reducing demolding force according to claim 1, characterized in that, The pressure cap has a plurality of first connecting holes on its circumference, and the top of the mold sleeve has a plurality of second connecting holes; the plurality of first connecting holes and the plurality of second connecting holes correspond one-to-one, and connecting members are inserted into the first connecting holes and the second connecting holes so that the pressure cap is connected to the mold sleeve.

5. The powder metallurgy mold for reducing demolding force according to any one of claims 1-4, characterized in that, The inner wall of the mold core cavity is provided with a first conical surface, which gradually slopes outward from bottom to top; the first conical surface is formed as the first guide portion.

6. The powder metallurgy mold for reducing demolding force according to claim 5, characterized in that, The outer wall of the mold core is provided with a second conical surface, which gradually slopes outward from bottom to top, and the second conical surface slides in fit with the first conical surface; the second conical surface is formed as the second guide portion.

7. The powder metallurgy mold for reducing demolding force according to any one of claims 1-4, characterized in that, The mold core is provided in four parts, and the four mold cores together form the molding cavity.

8. The powder metallurgy mold for reducing demolding force according to any one of claims 1-4, characterized in that, The powder metallurgy mold further includes an upper punch, a first lower punch, and a second lower punch. The upper punch moves from top to bottom towards the top of the mold core. The first lower punch passes through the mold core and can move from bottom to top towards or away from the bottom of the mold core. One end of the second lower punch is formed into a forming section. The bottom end of the second lower punch passes through the first lower punch and can move up and down along the mold core to drive the forming section to move up and down. The outer peripheral wall of the forming section cooperates with the inner sidewall of the mold core to form the forming cavity.

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