Metal powder metallurgy forming die based on the processing of hollow products

Abstract

The present invention discloses a metal powder metallurgy forming die based on the processing of hollow products. Based on the basic working principle of powder metallurgy, the movement mode of the upper die core is first improved. Its essence is that the upper die core does not directly provide extrusion force, but generates a secondary sliding process of upward movement during the pressing action. Its purpose is to preferentially reduce the extrusion force to avoid the problem of powder material overflow and waste. However, the upper die core is still a key structure during the pressing process. In addition, several second-order feeding pipes are arranged in accordance with the structural shape of the workpiece body. The second-order feeding pipes cooperate with the pressing and forming process to perform secondary feeding actions. Synchronous feeding is carried out on the basis of actively causing the problem of "lack of material". The powder material is evenly filled in cooperation with the extrusion method of the upper die core. During the overall process, it is also necessary to cooperate with the secondary feeding action to judge the completion degree of the overall pressing action based on the displacement change generated by the ejector core.

Description

Technical Field

[0001] The present invention relates to the technical field of powder metallurgy, and particularly to a metal powder metallurgy forming die based on the processing of hollow products. Background Art

[0002] The essence of the powder metallurgy process is to press and form metal powders, non-metal powders or mixtures of both through pressurization / high temperature. It is applicable to products with complex structural shapes. Referring to the relevant content in the publication number CN103817326A, it is commonly seen in the processing of gear parts.

[0003] Taking gear parts as an example and considering material cost savings, conventional gear parts will be provided with several optimized structures such as holes in addition to the installation hole positions. Therefore, the punches used in the forming die need to be customized according to the workpiece structure. It should be noted that the amount of powder in a single forming process is relatively consistent. However, after the punch uniformly enters the die cavity, affected by the structure and shape of the punch, some powder is ejected and lacks in quantity. In addition, it will also affect the powder filling uniformity, and ultimately affect the subsequent forming quality.

[0004] For this, the present application proposes a solution. Summary of the Invention

[0005] The purpose of the present invention is to provide a metal powder metallurgy forming die based on the processing of hollow products. For the powder metallurgy process of special products, due to the relatively special structure, when the punch enters the cavity, affected by the structure and shape of the punch, it directly affects the powder filling uniformity and then affects the subsequent forming quality.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A metal powder metallurgy forming die based on the processing of hollow products includes a lower die base, an upper pressure seat, an upper die core, a blank holder, a workpiece body and a hydraulic power cylinder. The blank holder is located inside the lower die base. A cavity corresponding to the workpiece body is formed inside the lower die base through the blank holder. The upper die core is slidably connected in the cavity.

[0007] A directional sliding seat is installed on the upper surface of the upper die core. The directional sliding seat is slidably connected along the height direction inside the upper pressure seat. A plurality of second-order injection pipes corresponding to the workpiece body are installed in the directional sliding seat. A directional insertion core column corresponding to the inside of the blank holder is arranged at the lower side position of the second-order injection pipe, and the upper end of the second-order injection pipe is set as a supplementary material position.

[0008] It is further set that: the upper pressure seat and the blank holder are slidably connected along the height direction of the lower die base through the hydraulic power cylinder.

[0009] Further set as: A plurality of first-order springs are installed between the upper pressing seat and the directional sliding seat, and the upper end part of the second-order injection tube is slidably connected to the upper pressing seat.

[0010] Further set as: The lower end of the second-order injection tube extends into the cavity, and an anti-inclined angle is provided at the lower end position of the second-order injection tube, and an inclined angle corresponding to the anti-inclined angle is provided at the upper end position of the directional core insertion column.

[0011] Further set as: A ejector core is slidably installed vertically inside the directional core insertion column, and the top end position of the ejector core is set as a conical angle.

[0012] Further set as: A displacement sensor is installed at the internal position corresponding to the lower side of the directional core insertion column of the material supporting seat, the top end position of the transmission rod of the displacement sensor is installed on the lower side position of the ejector core, and a second-order spring is installed at the external position of the transmission rod of the displacement sensor.

[0013] Further set as: The directional core insertion column is slidably connected at the internal position of the material supporting seat, and the low point plane of the inclined angle in the directional core insertion column is located at the lower side position of the one-half plane of the workpiece body along the thickness direction.

[0014] The present invention has the following beneficial effects:

[0015] 1. Based on the basic working principle of powder metallurgy, first, the movement mode of the upper die core is improved. More specifically, it is described as follows: In the pressing and forming process, the "material shortage" problem of the powder material is actively caused, and the connection mode of the upper die core is changed. The upper die core does not directly provide the extrusion force, but generates an upward secondary sliding process during the pressing action. First, the extrusion force is reduced to avoid the problem of powder material overflow and waste. However, the upper die core is still a key structure in the pressing process.

[0016] 2. Based on the above content, several corresponding second-order injection tubes are set for the structural shape of the workpiece body. The key of the second-order injection tube is to perform a secondary feeding action in cooperation with the actively caused "material shortage" problem. The second-order injection tube moves synchronously during the downward movement of the upper die core, and when performing the secondary feeding action after moving to the corresponding distance, the key lies in: During the cooperation with the secondary feeding action, the vertical movement of the ejector core is caused by the extrusion force generated by the powder material, so as to detect the movement mode and movement rate of the ejector core in real time by the displacement sensor, and judge the completion degree of the overall pressing action based on the above content, so as to ensure that a complete product body is obtained after the powder material is fully filled. Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 Structural schematic diagram of a metal powder metallurgy forming die for processing hollow products proposed by the present invention;

[0019] Figure 2 In the metal powder metallurgy forming die for processing hollow products proposed by the present invention Figure 1 Cross-sectional view;

[0020] Figure 3 Structural schematic diagram of the upper die core and the lower die base in the metal powder metallurgy forming die for processing hollow products proposed by the present invention;

[0021] Figure 4 In the metal powder metallurgy forming die for processing hollow products proposed by the present invention Figure 3 Cross-sectional view;

[0022] Figure 5 Cross-sectional view of the second-order injection pipe in the metal powder metallurgy forming die for processing hollow products proposed by the present invention;

[0023] Figure 6 In the metal powder metallurgy forming die for processing hollow products proposed by the present invention Figure 5 Partial schematic diagram.

[0024] In the figure: 1. Upper pressure seat; 2. Lower die base; 3. Second-order injection pipe; 4. First-order spring; 5. Directional sliding seat; 6. Upper die core; 7. Material supporting seat; 8. Hydraulic power cylinder; 9. Displacement sensor; 10. Directional inserting core column; 11. Ejector core; 12. Second-order spring; 13. Workpiece body. Detailed implementation manners

[0025] The following will clearly and completely describe the technical solutions of the present invention in combination with the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] Embodiment 1: In the powder metallurgy process of special products, due to the relatively special structure, when the punch punches into the cavity, the shape of the punch structure directly affects the uniformity of powder filling and the subsequent molding quality. The following technical solutions are proposed:

[0027] Reference Figures 1 to 6 The metal powder metallurgy forming die based on hollow product processing in this embodiment includes a lower die seat 2, an upper press seat 1, an upper die core 6, a support seat 7, a workpiece body 13 and a hydraulic power cylinder 8. The support seat 7 is located inside the lower die seat 2. A cavity corresponding to the workpiece body 13 is formed inside the lower die seat 2 through the support seat 7, and the upper die core 6 is slidably connected in the cavity;

[0028] A directional slide 5 is installed on the upper surface of the upper mold core 6, and the directional slide 5 is slidably connected inside the upper pressure seat 1 along its height direction. A plurality of second-order injection tubes 3 corresponding to the workpiece body 13 are installed in the directional slide 5, and a directional core column 10 corresponding to the inside of the support seat 7 is arranged on the lower side of the second-order injection tube 3, and the upper end of the second-order injection tube 3 is arranged as a filling position. The upper pressure seat 1 and the support seat 7 are slidably connected along the height direction of the lower mold seat 2 through a hydraulic power cylinder 8.

[0029] Basic principle: The essence of powder metallurgy process is compression molding, which is specifically applied to hollow products such as gear parts. In the compression molding process, the punch needs to be reset according to the product structure and shape. In this regard, the structure and shape of the second-stage injection pipe 3 and related continuations are not described in the present invention. It should be noted that:

[0030] In the specific operation process, the upper die core 6 and the support seat 7 are first reset to the initial position, and then the powder raw materials after the proportioning are put into the cavity. Under the power of the hydraulic power cylinder 8, the upper die core 6 is driven to be completely squeezed into the cavity, and the powder raw materials are fully pressed to form a workpiece body with a corresponding structural shape. In this process, it should be explained that:

[0031] Because the second-stage injection tube 3 will also be immersed in the cavity, a corresponding product structure is formed for the local position of the second-stage injection tube 3. After the pressing is completed, the upper pressing seat 1 is reset, and the supporting seat 7 is driven upward by the hydraulic power cylinder 8, so that the pressed workpiece body 13 is squeezed out of the cavity for the next pressing and forming process.

[0032] Embodiment 2: This embodiment improves the conventional powder metallurgy process, as follows:

[0033] A plurality of first-order springs 4 are installed between the upper pressing seat 1 and the directional sliding seat 5. The upper end part of the second-order feeding pipe 3 is slidably connected to the upper pressing seat 1. The lower end of the second-order feeding pipe 3 extends into the cavity, and an anti-bevel is provided at the lower end position of the second-order feeding pipe 3. An inclined angle corresponding to the anti-bevel is provided at the upper end position of the directional core inserting column 10. A ejector core 11 is slidably installed vertically inside the directional core inserting column 10, and the top end position of the ejector core 11 is provided with a conical angle.

[0034] A displacement sensor 9 is installed at the internal position corresponding to the lower side of the directional core inserting column 10 in the material supporting seat 7. The top end position of the transmission rod of the displacement sensor 9 is installed at the lower side position of the ejector core 11, and a second-order spring 12 is installed at the external position of the transmission rod of the displacement sensor 9. The directional core inserting column 10 is slidably connected at the internal position of the material supporting seat 7, and the low point plane of the inclined angle in the directional core inserting column 10 is located at the lower side position of the half-plane of the workpiece body 13 in the thickness direction.

[0035] Solution description: The key of the conventional powder metallurgy technology lies in the pressing process. Specifically, the direct pressing method is adopted. However, in this process, on the one hand, it will cause the overflow of the powder material, resulting in the problem of material shortage in the workpiece body 13. In addition, the uneven filling of the powder material will also affect the forming quality of the workpiece body 13. In view of this problem, the present invention proposes the following pressing process for this problem:

[0036] S1: In this embodiment, the upper die core 6 is still used as the key structure in the pressing process. However, the movement process of the upper die core 6 is different. Specifically, when the upper die core 6 moves into the cavity and contacts the powder material and starts to press, due to the resistance of the powder material, an upward reaction force is generated on the upper die core 6. As a result, the directional sliding seat 5 starts to move upward in the upper pressing seat 1 in the direction from bottom to top under the reaction force from the upper die core 6. The purpose is to reduce the extrusion force on the powder material and avoid directly causing the overflow of the powder material. During this process, when the first-order spring 4 is continuously compressed and reaches the maximum compression amount, the directional sliding seat 5 will not continue to move upward. Thus, the upper die core 6 provides a "complete" extrusion force to the powder material.

[0037] S2: Based on the content of S1, as the upper die core 6 continues to move, the second-order feeding pipe 3 will also move downward synchronously. During this process, since the lower end of the second-order feeding pipe 3 is located below the upper die core 6, the cavity can be replenished through the second-order feeding pipe 6. Its essence is that replenishment is carried out synchronously during the pressing action. Thus, it can be understood that the obvious difference between the present invention and the conventional powder metallurgy is that in the initial state, not all the quantitative powder materials are injected into the cavity, but the pressing action and the feeding action are carried out synchronously.

[0038] Embodiment 3: The following description is made by combining the relevant contents in Embodiment 1 and Embodiment 2:

[0039] S3: If the weight of the powder material required for single - press forming is M, then in the initial state, only 0.85xM of the powder material is put into the cavity. In actual situations, there is a problem of material shortage in the workpiece body 13 obtained by pressing. Therefore, it is necessary to continuously supplement 0.15 - 0.17xM of the powder material through multiple second - order feeding pipes 3. Specifically, it is shown as follows:

[0040] Because there is a tendency for the directional sliding seat 5 to move upward during the pressing process. When the lower side of the upper pressing seat 1 just touches the upper surface of the lower die base 2, it indicates that the overall pressing process is completed. And combined with Figure 6 it is described as follows: As the pressing action continues, the distance between the lower end of the second - order feeding pipe 3 and the upper side of the directional core - inserting column 10 gradually decreases. However, after the pressing action is completed, there is still a gap between the lower end of the above - mentioned second - order feeding pipe 3 and the upper side of the directional core - inserting column 10;

[0041] And referring to Figure 5 , because the second - order feeding pipe 3 needs to perform a secondary feeding action, the remaining powder material can be injected by means of pressurization. During this process, the ejector core 11 shows a downward movement trend due to the extrusion force from the powder material. Until the top position of the ejector core 11 moves to a position lower than the upper plane of the directional core - inserting column 10, the powder material is replenished into the cavity again;

[0042] S4: It also needs to be explained that: because the ejector core 11 continuously moves downward due to the extrusion force of the powder material, the displacement sensor 9 can continuously detect the moving speed of the ejector core 11. The moving speed of the ejector core 11 is an important parameter for feedback of the pressing process. The specific reason is that: if there is a serious material shortage problem inside the cavity, and when the top of the ejector core 11 moves to the corresponding upper position of the directional core - inserting column 10, a part of the powder material can quickly fill into the cavity. Then, the powder material inside the second - order feeding pipe 3 can be replenished into the cavity in a "simpler" way;

[0043] On the contrary, when the material shortage degree inside the cavity is low or there is no obvious material shortage problem, the powder material inside the second - order feeding pipe 3 will not enter the cavity again. Then, the pressure generated by the powder material replenished inside the second - order feeding pipe 3 only acts on the ejector core 11, causing the ejector core 11 to continue to move downward. And during this process, the moving rate of the ejector core 11 is proportional to the powder material replenished inside the second - order feeding pipe 3, that is, the greater the pressure generated by the powder material, the faster its moving rate;

[0044] S5: Integrate the content in S1 - S4. If the thickness of the workpiece body 13 is H, then the thickness of the cavity should be H. That is, when the distance between the upper die core 6 and the blank holder 7 is equal to H, it indicates that the pressing is completed. However, it should be noted that during the pressing and forming operation, when the distance between the upper die core 6 and the blank holder 7 is greater than or equal to 1.09 - 1.15xH, a secondary feeding operation is performed through the second-order feeding pipe 3. And during the process of the upper die core 6 continuing to move downward by 0.09 - 0.15xH, the display value in the displacement sensor 9 needs to be fully utilized. The feeding amount per unit time in the secondary feeding operation performed by the second-order feeding pipe 3 is constant;

[0045] If there are obvious fluctuations in the display of the displacement sensor 9, then the moving speed of the upper die core 6 needs to be further controlled. The purpose is: to complete the pressing and forming operation by providing a stable extrusion force, and referring to Figure 6 , the purpose of restricting the low-point plane of the inclined angle in the directional insert core column 10 to be located below the one-half plane of the workpiece body 13 in the thickness direction is that: the powder material supplemented from the second-order feeding pipe 3 is mainly concentrated in the lower side position of the cavity. Due to the extrusion force, the powder material accumulated in the lower side position is "spread" into the remaining material-deficient spaces.

[0046] In summary: Based on the basic working principle of powder metallurgy, first, the moving mode of the upper die core is improved. Its essence is that the upper die core does not directly provide the extrusion force, but there is a secondary sliding process of moving upward during the pressing operation. The purpose is to preferentially reduce the extrusion force to avoid the problem of powder material overflow and waste. However, the upper die core is still a key structure during the pressing process. In addition, several second-order feeding pipes are arranged in accordance with the structural shape of the workpiece body. The second-order feeding pipes cooperate with the pressing and forming process to perform a secondary feeding operation. Synchronous feeding is carried out on the basis of actively creating the problem of "material deficiency". The powder material is evenly filled in cooperation with the extrusion method of the upper die core. During the overall process, it is also necessary to judge the completion degree of the overall pressing operation in cooperation with the displacement change of the ejector core caused by the secondary feeding operation.

[0047] The above is an example and explanation of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the structure of the invention or exceed the scope defined by this claim book, they should fall within the protection scope of the present invention.

Claims

1. A metal powder metallurgy forming die based on the processing of hollow products, comprising a lower die base (2), an upper pressing seat (1), an upper die core (6), a blank holder seat (7), a workpiece body (13) and a hydraulic power cylinder (8), characterized in that, The stock supporting seat (7) is located inside the lower die base (2). A cavity corresponding to the workpiece body (13) is formed inside the lower die base (2) through the stock supporting seat (7), and the upper die core (6) is slidably connected in the cavity; A directional sliding seat (5) is installed at the upper surface position of the upper die core (6). The directional sliding seat (5) is slidably connected along the height direction inside the upper pressure seat (1). A plurality of second-order injection pipes (3) corresponding to the workpiece body (13) are installed in the directional sliding seat (5). A directional inserting core column (10) corresponding to the inside of the stock supporting seat (7) is arranged at the lower side position of the second-order injection pipe (3), and the upper end of the second-order injection pipe (3) is set as the feeding position; The upper end part of the second-order injection pipe (3) is slidably connected with the upper pressure seat (1). The lower end of the second-order injection pipe (3) extends into the cavity, and an anti-inclined angle is arranged at the lower end position of the second-order injection pipe (3). An inclined angle corresponding to the anti-inclined angle is opened at the upper end position of the directional inserting core column (10). A ejector core (11) is slidably installed vertically inside the directional inserting core column (10). The top end position of the ejector core (11) is set as a conical angle. A displacement sensor (9) is installed at the internal position corresponding to the lower side of the directional inserting core column (10) in the stock supporting seat (7). The top end position of the transmission rod of the displacement sensor (9) is installed at the lower side position of the ejector core (11), and a second-order spring (12) is installed at the external position of the transmission rod of the displacement sensor (9).

2. The metal powder metallurgy forming die based on the processing of hollow products according to claim 1, characterized in that, The upper pressure seat (1) and the stock supporting seat (7) are slidably connected along the height direction of the lower die base (2) through a hydraulic power cylinder (8).

3. The metal powder metallurgy forming die based on the processing of hollow products according to claim 1, wherein A plurality of first-order springs (4) are installed between the upper pressure seat (1) and the directional sliding seat (5).

4. The metal powder metallurgy forming die based on the processing of hollow products according to claim 1, characterized in that, The directional inserting core column (10) is slidably connected at the internal position in the stock supporting seat (7), and the low point plane of the inclined angle in the directional inserting core column (10) is located at the lower side position of the one-half plane of the workpiece body (13) along the thickness direction.

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