A rubber sleeve device for metal powder press forming

Abstract

The utility model provides a rubber sleeve device for metal powder press forming relates to powder metallurgy press forming technology, specifically discloses rubber sleeve, one end of rubber sleeve has opening, the other end of rubber sleeve is closed, the inner diameter of rubber sleeve gradually reduces from opening end side to closed end, the inner wall of rubber sleeve and the bottom wall of rubber sleeve closed end are circular table shape, the opening end of rubber sleeve is embedded with rubber sleeve inner plug, the side wall opposite rubber sleeve inner plug and rubber sleeve bottom wall is equipped with the inner chamber of circular table shape, the large diameter end of inner chamber is towards rubber sleeve closed end side, the opening end of rubber sleeve is equipped with closed structure, the inner chamber of rubber sleeve has certain taper, solve the problem that the length direction diameter of compaction is not uniform, the inner wall of rubber sleeve closed end and rubber sleeve inner plug end face respectively are circular table shape structure, make both ends all have the radian of appropriate size, solve the problem of material clamping, material plugging in subsequent processing, solve the problem that the end performance difference is bigger because of the radian of both ends is too big.

Description

Technical Field

[0001] This utility model relates to the field of powder metallurgy pressing and molding technology, and more specifically, to a rubber sleeve device for pressing and molding metal powder. Background Technology

[0002] Tungsten, with its advantages of high melting point, high strength, excellent thermal and electrical conductivity, and low coefficient of thermal expansion, is used to manufacture electrode materials such as cathode electrodes and heating electrodes, as well as filaments for fluorescent lamps and halogen lamps, and cutting wires such as diamond wire cutting wires. It is also widely used in rare earth smelting, glass electric melting furnaces, electric light source parts, electronic components, high-hardness materials, and lifting ropes for single crystal furnaces.

[0003] Tungsten rods, tungsten bars, and tungsten wires are mainly produced using powder metallurgy and rolling processes. The sintered billets are round bars, and the feeding sleeve device in the pressing and forming process is crucial in determining the shape, size, and appearance quality of the sintered billets. Traditional round bar sleeves typically have a flat-top design at the bottom and for the sealing plug, resulting in flat ends on both sides of the pressed and sintered billets. This easily leads to material jamming and blockage at the feed end during subsequent rotary forging or rolling. Chinese utility model patent CN207288892U, "A Sleeve Device for Molybdenum Rods," addresses this by shaping the sleeve, plug, and sheath. The inner wall of the closed end of the sleeve and the end face of the inner plug facing the sleeve cavity at the open end of the sleeve are respectively provided with symmetrical spherical surfaces of the same diameter as the inner cavity of the sleeve. This ensures that both ends of the prepared molybdenum rod are hemispherical, solving the problem of material jamming and blockage during subsequent use. However, the following drawbacks still exist:

[0004] The cylindrical inner cavity of the sleeve results in a large taper in the diameter of the pressed blank. Because a certain amount of vibration is required during loading to ensure smooth powder loading, the powder loaded into the sleeve first undergoes a longer vibration time. Under the influence of the powder's own gravity, the powder loaded first at the closed bottom end of the sleeve is more compact, while the powder loaded later at the open top end is more loose. This results in the diameter of the pressed blank at the closed end of the sleeve being larger than that at the open end. Furthermore, the longer the pressed blank, the greater the diameter taper. This leads to different deformation amounts during subsequent calendering of the round bar, altering product performance and negatively impacting product quality stability.

[0005] The prepared bars are designed with hemispherical ends, and the diameter transition of the hemispheres is relatively large. This results in significant differences in the amount of deformation at the ends during subsequent rolling processing, leading to noticeable differences in end performance. To ensure product quality, the ends may need to be cut off during subsequent processing, resulting in a decrease in product yield. Utility Model Content

[0006] The purpose of this invention is to provide a rubber sleeve device for metal powder pressing and molding, which addresses the shortcomings of the prior art and solves the problems mentioned in the background.

[0007] The technical solution of this utility model is implemented as follows:

[0008] This utility model provides a sleeve device for metal powder pressing and molding, including a sleeve, one end of which has an opening and the other end of which is closed. The inner diameter of the sleeve gradually decreases from the open end to the closed end. The inner wall of the sleeve and the bottom wall of the closed end of the sleeve form a frustum-like structure. An inner plug is embedded in the open end of the sleeve. The inner plug has a frustum-like cavity on its side wall opposite to the bottom wall of the sleeve. The large diameter end of the cavity faces the closed end of the sleeve. The open end of the sleeve has a closing structure.

[0009] In some technical solutions of this utility model, a protective sleeve is also included. One end of the protective sleeve has an opening, the other end of the protective sleeve is closed, a through hole is provided on the closed end of the protective sleeve, and the rubber sleeve is embedded in the protective sleeve.

[0010] In some technical solutions of this utility model, the inner wall of the rubber sleeve and the bottom wall of the rubber sleeve have a smooth transition.

[0011] In some technical solutions of this utility model, the closed structure includes an outer plug sleeve embedded in the rubber sleeve, an outer plug of the rubber sleeve is installed inside the outer plug sleeve, and the free end of the outer plug sleeve is folded over and sleeved on the outer side wall of the rubber sleeve.

[0012] In some technical solutions of this utility model, the diameter of the open end of the rubber sleeve is larger than the diameter of the closed end of the rubber sleeve.

[0013] In some technical solutions of this utility model, the large diameter of the inner plug of the rubber sleeve is smoothly transitioned to the rubber sleeve.

[0014] Compared with existing technologies, this utility model has at least the following advantages or beneficial effects: The inner cavity of the rubber sleeve has a certain taper, and the diameter of the open end is larger than that of the closed end, improving the uniformity of the pressed blank diameter. The inner wall of the closed end of the rubber sleeve and the end face of the inner plug of the rubber sleeve facing the cavity of the rubber sleeve are respectively provided with a frustum-like shape, so that the prepared round strip has a suitable curvature at both ends. This can solve the problem of material jamming and blockage in the subsequent processing of the round strip, and also avoid the problem of large differences in end performance caused by excessive curvature at both ends, thereby improving product quality. The outer plug sleeve is made of soft elastic material and can be folded over and wrapped around the outer wall of the open end of the rubber sleeve. On the one hand, it can improve the sealing performance of the rubber sleeve and prevent liquid immersion during the pressing process; on the other hand, it has low rigidity requirements for the rubber sleeve and can be used for thin-walled rubber sleeves. The rubber sleeve is placed in the inner cavity of the rigid sheath, which can ensure that the rubber sleeve does not deform significantly when the powder is vibrated and loaded, thereby ensuring that the surface of the round strip is smooth and has good straightness. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the sheath structure.

[0017] Figure 3 This is a schematic diagram of the rubber sleeve structure.

[0018] Figure 4 This is a schematic diagram of the inner plug of the rubber sleeve.

[0019] Figure 5 This is a schematic diagram of the structure of the rubber sleeve outer plug.

[0020] Figure 6 This is a schematic diagram of the outer plug sleeve.

[0021] Reference numerals in the attached drawings: 1. Sheath; 2. Rubber sleeve; 3. Inner plug of rubber sleeve; 4. Outer plug of rubber sleeve; 5. Outer plug sleeve; 6. Through hole; 7. First chamfer structure; 8. Inner cavity of rubber sleeve; 9. First type of frustum structure; 10. Second type of frustum structure; 11. Second chamfer structure; 12. Third chamfer structure; 13. Fourth chamfer structure. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0024] Example

[0025] This utility model provides a rubber sleeve device for metal powder pressing and molding, such as... Figures 1-6 As shown, the device includes a cylindrical rubber sleeve 2 with an opening at one end and a closed end at the other. The inner diameter of the rubber sleeve 2 gradually decreases from the open end to the closed end. A first-type frustum-shaped structure 9 is provided between the inner cavity 8 of the rubber sleeve and the bottom wall of the rubber sleeve 2. A rubber sleeve inner plug 3 is embedded in the open end of the rubber sleeve 2. The inner plug 3 has a frustum-shaped inner cavity on its side wall opposite to the bottom wall of the rubber sleeve 2, with the larger diameter end of the inner cavity facing the closed end of the rubber sleeve 2. A sealing structure is provided on the open end of the rubber sleeve 2. Metal powder is filled into the inner cavity 8 of the rubber sleeve 2 from the open end. Then, the rubber sleeve inner plug 3 is inserted into the open end of the rubber sleeve 2, so that the metal powder at the open end of the rubber sleeve 2 also fills the frustum-shaped inner cavity of the inner plug 3. The sealing structure seals the open end to prevent powder backflow or loosening and to prevent liquid from entering the powder during pressing in a liquid medium. During the pressing process, external pressure is applied to the outer wall of the sleeve 2, causing the sleeve 2 to gradually shrink and force the powder to undergo plastic deformation, forming a molded product with a similar shape, specific size, and density to the inner cavity 8 of the sleeve and the inner cavity of the inner plug 3. Due to the gradual change in the inner diameter of the sleeve 2's inner cavity, the denser powder initially loaded at the closed end of the sleeve 2 fills a smaller space, while the looser powder loaded later at the open end fills a larger space, guiding the powder loading to be more uniform, reducing density gradients, and solving the problem of uneven diameter along the length of the pressed blank. The design of the first type of frustum structure 9 at the closed end of the sleeve 2 and the second type of frustum structure 10 in the inner cavity of the inner plug 3 creates a "trumpet mouth" effect with small end faces at both ends and a large middle face, guiding the powder to converge towards the center. This allows the end powder to be pressed into an arc of appropriate size, solving the problems of material jamming and blockage during subsequent processing. It also avoids the problem of large differences in end performance caused by excessive arc at both ends, thereby improving product quality.

[0026] In some technical solutions of this utility model, a protective sleeve 1 is also included. One end of the protective sleeve 1 is open, and the other end is closed. A through hole 6 is provided on the closed end of the protective sleeve 1, and a rubber sleeve 2 is embedded inside the protective sleeve 1. During pressing, the pressure medium acts evenly on the outer wall of the rubber sleeve 2 through the through hole 6 of the protective sleeve 1, the outer wall of the protective sleeve 1, and the gap between the open end of the protective sleeve 1 and the outer wall of the rubber sleeve 2, causing it to contract evenly and achieving isostatic pressing. The protective sleeve 1 acts as a rigid support, providing a certain degree of restriction and protection for the rubber sleeve 2, preventing significant deformation of the rubber sleeve 2. The protective sleeve 1 bears the load of the external pressure medium, reducing fatigue wear of the rubber sleeve 2. The protective sleeve 1 is designed to be compatible with different pressing processes such as hydraulic and pneumatic pressing.

[0027] Preferably, the inner diameter of the sheath 1 is larger than the outer diameter of the rubber sleeve 2, and the height of the sheath 1 is lower than the height of the rubber sleeve 2.

[0028] In some technical solutions of this utility model, the inner cavity 8 of the rubber sleeve and the bottom wall of the rubber sleeve 2 have a smooth transition. The connection between the inner cavity 8 of the rubber sleeve and the bottom wall of the rubber sleeve 2 adopts an arc transition (not a right angle). During pressing, the powder flows along the smooth curved surface without sharp turns. The arc design disperses the pressing pressure and avoids the accumulation of powder at corners due to shear force. The smooth transition avoids the powder getting stuck at right angles, improving the smoothness of demolding. The arc transition enhances the edge strength of the blank and eliminates stress concentration, making the edge density of the blank consistent with the center.

[0029] In some technical solutions of this utility model, the sealing structure includes an outer plug sleeve 5 embedded in a rubber sleeve 2, and a rubber sleeve outer plug 4 installed inside the outer plug sleeve 5. The free end of the outer plug sleeve 5 is folded over and fitted onto the outer side wall of the rubber sleeve 2. During pressing, the outer plug sleeve 5 and the rubber sleeve outer plug 4 work together to lock the open end. The folded portion enhances the sealing performance. The outer plug sleeve 5 and the rubber sleeve outer plug 4 form an interlocking double sealing structure. The folded portion fits against the outer wall of the rubber sleeve 2 to prevent powder leakage and pressure medium entry. The folded structure adapts to the contraction / expansion of the rubber sleeve 2 to maintain sealing performance. The modular design of the outer plug sleeve 5 and the rubber sleeve outer plug 4 facilitates cleaning and maintenance. Preferably, the outer plug sleeve 5 is made of a soft elastic material, preferably silicone, rubber, latex, or other soft elastic materials, and the wall thickness is preferably 0.5-3.0 mm.

[0030] Preferably, the outer diameters of the inner plug 3 and the outer plug 5 of the rubber sleeve are adapted to the inner diameter of the opening end of the rubber sleeve 2, and the diameter difference is preferably within 2 mm.

[0031] In some technical solutions of this utility model, the diameter of the open end of the rubber sleeve 2 is larger than the diameter of the closed end of the rubber sleeve 2. The large diameter design of the open end matches the low bulk density of the powder and appropriately increases the diameter of the pressed blank. The small diameter design of the closed end matches the high bulk density of the powder, avoiding the pressed blank diameter from being too large and improving the uniformity of the pressed blank diameter. The inner diameter of the rubber sleeve 2 gradually decreases from the open end to the closed end to avoid significant collision between the pressed blank and the rubber sleeve 2 during demolding, which could lead to breakage.

[0032] Preferably, the diameter of the open end of the rubber sleeve 2 is 5-15% larger than that of the closed end.

[0033] In some technical solutions of this utility model, the large-diameter end of the inner plug 3 of the rubber sleeve smoothly transitions to the inner diameter of the rubber sleeve 2. The inner cavity of the inner plug 3 of the rubber sleeve is smoothly connected to the inner cavity 8 of the rubber sleeve. The powder flows gently from the inner cavity 8 of the rubber sleeve into the frustum-shaped cavity of the inner plug without abrupt changes in flow resistance, avoiding turbulence or accumulation caused by abrupt changes in the powder flow path, and improving the structural strength of the blank after the powder material is pressed and formed.

[0034] In some technical solutions of this utility model, a first type of frustum structure 9 is formed between the inner cavity 8 of the rubber sleeve and the bottom wall of the rubber sleeve 2. During loading, the powder gradually fills the frustum-shaped inner cavity. During pressing, external pressure is applied to the outer wall of the rubber sleeve 2, and the rubber sleeve 2 gradually shrinks, forcing the powder to undergo plastic deformation, forming a compact with a shape similar to the frustum-shaped inner cavity of the rubber sleeve 2. This gives one end of the compact a suitable curvature, which solves the problems of material jamming and blockage during subsequent processing, and avoids the problem of large differences in end performance caused by excessive curvature at both ends, thereby improving product quality.

[0035] Preferably, the inner wall of the closed end of the rubber sleeve 2 and the end face of the inner plug 3 facing the cavity of the rubber sleeve 2 are respectively provided with a frustum-shaped structure, so that the prepared round strip has a suitable curvature at both ends, which meets the requirement of turning the ends over for processing in subsequent processing.

[0036] Preferably, the diameter of the small end of the first type of frustum structure 9 is 40-80% of the diameter of the large end of the first type of frustum structure 9, and the height of the first type of frustum structure 9 is 50-150% of the diameter of the large end.

[0037] Preferably, the second type of frustum structure 10 is similar to the first type of frustum structure 9, with the diameter of the small end preferably being 40-80% of the diameter of the large end, and the height preferably being 50-150% of the diameter of the large end.

[0038] In some technical solutions of this utility model, a first chamfer structure 7 is provided on the outer end face of the closed end of the rubber sleeve 2, a second chamfer structure 11 is provided on both ends of the outer plug 4, a third chamfer structure 12 is provided on the outer bottom of the closed end of the outer plug sleeve 5, and a fourth chamfer structure 13 is provided on the inner bottom of the closed end of the outer plug sleeve 5. The first chamfer structure 7, the second chamfer structure 11, the third chamfer structure 12, and the fourth chamfer structure 13 can be right angles or rounded corners, and the chamfer size is preferably 1-10mm.

[0039] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A rubber sleeve device for pressing and molding metal powder, characterized in that, Includes a rubber sleeve (2), one end of which has an opening and the other end of which is closed. The inner diameter of the rubber sleeve (2) gradually decreases from the open end to the closed end. The inner wall of the rubber sleeve (2) and the bottom wall of the closed end of the rubber sleeve (2) form a frustum-like structure. The open end of the rubber sleeve (2) is fitted with a rubber sleeve inner plug (3). The side wall of the rubber sleeve inner plug (3) opposite to the bottom wall of the rubber sleeve (2) is provided with a frustum-like inner cavity. The large diameter end of the inner cavity faces the closed end of the rubber sleeve (2). The open end of the rubber sleeve (2) is provided with a closed structure.

2. The rubber sleeve device for pressing and molding metal powder according to claim 1, characterized in that, It also includes a sheath (1), one end of which has an opening and the other end of which is closed. A through hole (6) is provided on the closed end of the sheath (1), and the rubber sleeve (2) is embedded in the sheath (1).

3. The rubber sleeve device for pressing and molding metal powder according to claim 1, characterized in that, The inner wall of the rubber sleeve (2) and the bottom wall of the rubber sleeve (2) are smoothly transitioned.

4. The rubber sleeve device for pressing and molding metal powder according to claim 1, characterized in that, The closed structure includes an outer plug sleeve (5) embedded in the rubber sleeve (2), and a rubber sleeve outer plug (4) is installed inside the outer plug sleeve (5). The free end of the outer plug sleeve (5) is folded over and fitted onto the outer side wall of the rubber sleeve (2).

5. The rubber sleeve device for pressing and molding metal powder according to claim 1, characterized in that, The diameter of the open end of the rubber sleeve (2) is larger than the diameter of the closed end of the rubber sleeve (2).

6. The rubber sleeve device for pressing and molding metal powder according to claim 1, characterized in that, The large-diameter end of the inner plug (3) of the rubber sleeve smoothly transitions to the inner wall of the rubber sleeve (2).

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