Ceramic pad for bearing powder metallurgy sintered part

Abstract

The utility model belongs to the technical field of powder metallurgy, and particularly relates to a ceramic pad for bearing a powder metallurgy sintered part. The ceramic pad is integrally formed by a ceramic material and comprises a bottom supporting platform and a group of side supporting blocks arranged around the periphery of the bottom supporting platform; the bottom supporting platform is provided with an annular surrounding edge and a network supporting body connected in an area defined by the surrounding edge. The upper side of the network support body is provided with a flat bearing surface for bearing the powder metallurgy sintered part, and a plurality of vertically through heat exchange holes are further distributed in the network support body; the side supporting blocks are arranged at intervals, the ends of the side supporting blocks are flush, and when the ceramic pads are stacked, the side supporting blocks bear the surrounding edge of the upper ceramic pad. A heat exchange notch is formed between every two adjacent side supporting blocks. The ceramic pad has excellent high temperature resistance, heat exchange efficiency, structural strength, bearing capacity and stacking stability in the sintering process of powder metallurgy parts, the influence of a sintering furnace on blank sintering can be effectively avoided, and the quality and production efficiency of sintered parts are remarkably improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of powder metallurgy, and in particular relates to a ceramic pad for carrying powder metallurgy sintered parts. Background Art

[0002] As an important method for preparing metal parts, powder metallurgy technology is widely used in the fields of automobiles, aviation, machinery, electronics, etc. One of its core steps is to sinter the pressed powder metallurgy blank at high temperature to achieve metallurgical bonding between powder particles and form dense parts with required physical, chemical and mechanical properties. However, many factors in the sintering process, such as sintering atmosphere, heating rate, holding time and the selection of sintering carrier, have a significant impact on the quality and production efficiency of the final product.

[0003] In the initial powder metallurgy sintering process, the blank is usually placed directly in the sintering furnace body. This direct contact method has the following problems: first, the furnace body material and the blank may produce physical or chemical reactions under high temperature conditions, resulting in surface contamination of the blank or changes in alloy composition, seriously affecting the performance of the sintered part; second, the direct contact of the furnace body has a greater impact on the local heating environment of the blank, resulting in uneven internal structure of the sintered part, warping and even cracking, affecting the dimensional accuracy and mechanical properties of the product; third, the direct placement method cannot achieve large-scale and efficient sintering operations, especially in mass production, the space utilization rate in the furnace is low and the production efficiency is limited.

[0004] To solve the above problems, the industry has tried to use various sintering carriers to carry powder metallurgy blanks. Among them, ceramic gaskets have become ideal sintering auxiliary tools due to their excellent high temperature resistance and chemical stability. However, in practical applications, the above problems cannot be completely solved, especially in terms of taking into account heat exchange efficiency, space utilization, durability and sintering quality. There are still obvious limitations. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides a ceramic pad for supporting a powder metallurgy sintered part.

[0006] The purpose of the utility model is to develop a new type of ceramic pad for supporting powder metallurgy sintered parts, which can not only effectively avoid the problems caused by direct contact with the furnace body, but also significantly improve the heat exchange efficiency, ensure the stable load of the sintered parts, and support efficient and stable multi-layer stacking sintering to meet the needs of the modern powder metallurgy industry for high-quality and high-efficiency sintering.

[0007] The utility model provides a ceramic pad for carrying powder metallurgy sintered parts, which is integrally formed from ceramic material and includes a bottom support platform and a group of side support blocks arranged around the outer periphery of the bottom support platform; the bottom support platform has an annular peripheral edge and a network support body connected to the area surrounded by the peripheral edge; the upper side of the network support body has a flat bearing surface for carrying the powder metallurgy sintered parts, and a number of heat exchange holes that pass through the network support body from top to bottom are distributed; the side support blocks are spaced apart from each other and have flush ends, and when the ceramic pads are stacked, they carry the peripheral edge of the upper ceramic pad; heat exchange gaps are formed between adjacent side support blocks.

[0008] As a further improvement of the above ceramic pad, the network support body includes a central limiting ring and a group of radiating support ribs connected in one piece; heat exchange holes are formed in the central limiting ring and between adjacent radiating support ribs.

[0009] As a further improvement of the above ceramic pad, in the network support body, 3 to 9 radial support ribs are radially connected from the central limiting ring to the surrounding area.

[0010] As a further improvement of the above ceramic pad, the area of ​​the region enclosed by the edge is S0, and the cross-sectional areas occupied by the heat exchange holes are S1, S2,…, Sn, respectively, then (S1+S2+…+Sn) / S0=0.55~0.90.

[0011] As a further improvement of the above ceramic pad, (S1+S2+…+Sn) / S0=0.62~0.85.

[0012] As a further improvement of the above-mentioned ceramic pad, a first limiting step is provided on the inner side of the top of the side support block, and a second limiting step is provided on the bottom edge of the surround; when the ceramic pads are stacked, the second limiting step of the upper ceramic pad is engaged with the first limiting step of the lower ceramic pad.

[0013] As a further improvement of the above ceramic pad, the surrounding edge is in a circular ring shape, and a second circular limiting step is formed along the bottom edge of the surrounding edge.

[0014] As a further improvement of the above ceramic pad, the surrounding edge is in a circular ring shape, and the side support blocks are arranged at equal intervals along the surrounding edge, and the number of the side support blocks is 3 to 9.

[0015] As a further improvement of the above ceramic pad, the perimeter of the surrounding edge is L0, and the perimeters occupied by the side support blocks are L1, L2, ..., Ln, respectively, then (L1+L2+...+Ln) / L0=0.35~0.70.

[0016] As a further improvement of the above ceramic pad, for any i,j∈{1,2, …,n}, (Li-Lj) / Li=-0.05~0.05.

[0017] Beneficial Effects

[0018] The ceramic pad for supporting powder metallurgy sintered parts provided by the utility model has excellent high temperature resistance, heat exchange efficiency, structural strength, load-bearing capacity and stacking stability during the sintering process of powder metallurgy parts, can effectively avoid the influence of the sintering furnace on the sintering of the blank, and significantly improve the quality and production efficiency of the sintered parts.

[0019] The ceramic pad is made of integrally formed ceramic material and has excellent high temperature resistance. It can maintain structural integrity and strength in a high temperature sintering environment and will not bond with the powder metallurgy blank, ensuring the smooth progress of the sintering process.

[0020] The network support body of the bottom support platform of the ceramic pad has heat exchange holes that run through the top and bottom, as well as heat exchange gaps between the side support blocks, forming an effective hot air flow path, accelerating heat transfer during the sintering process, improving temperature control accuracy, and at the same time improving sintering efficiency, which is beneficial to improving the internal structural uniformity of the sintered parts and improving product quality.

[0021] The annular edge and network support body of the bottom support platform of the ceramic pad jointly ensure the structural strength and rigidity, wherein the network support body can be a structure including a central limiting ring and radial supporting ribs, which not only reduces the weight, but also forms a stable supporting skeleton to ensure the structural integrity and bearing capacity under high temperature conditions. The central limiting ring can accurately limit the powder metallurgy parts with a central boss to prevent the parts from being placed skewed or moved, and improve the geometric accuracy of the parts after sintering and the performance consistency between batches.

[0022] The first limiting step on the inner side of the top of the side support block of the ceramic pad engages with the second limiting step on the bottom edge of the surrounding edge to ensure that the ceramic pads are accurately aligned when stacked, effectively preventing the stack from overturning due to furnace vibration or mesh belt movement, and is particularly suitable for mesh belt furnace sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 and Figure 2 It is a three-dimensional schematic diagram of a ceramic pad.

[0024] Figure 3 A top view of a ceramic pad.

[0025] Figure 4 Schematic diagram of two ceramic pads stacked together.

[0026] In the figure: 2, side support block; 11, surrounding edge; 12, network support body; 21, heat exchange gap; 22, first limiting step; 111, second limiting step; 121, bearing surface; 122, heat exchange hole; 123, central limiting ring; 124, radial support ribs. DETAILED DESCRIPTION

[0027] When manufacturing powder metallurgy parts, the powder metallurgy parts need to be sintered. In order to prevent the blank of the powder metallurgy parts from directly contacting the furnace body of the sintering furnace and affecting the sintering quality, the utility model provides a ceramic pad for carrying the powder metallurgy sintered parts.

[0028] The ceramic pad for supporting the powder metallurgy sintered part is formed from a ceramic material in one piece, which ensures the integrity, strength and high temperature resistance of the structure and can be well applied to high temperature sintering environments. In addition, the ceramic material itself has extremely strong stability and will not bond with the blank of the powder metallurgy part in a high temperature environment.

[0029] Structurally Figures 1 to 3 As shown, the ceramic pad includes a bottom support platform and a group of side support blocks 2 arranged around the periphery of the bottom support platform; the bottom support platform has an annular surrounding edge 11 and a network support body 12 connected to the area surrounded by the surrounding edge 11. The annular surrounding edge 11 and the network support body 12 jointly ensure the structural strength and rigidity of the bottom support platform. The upper side of the network support body 12 has a flat bearing surface 121 to carry the powder metallurgy sintered parts, ensuring that the powder metallurgy sintered parts are placed stably and bend due to unbalanced force during high-temperature sintering. There are also a number of heat exchange holes 122 that are connected up and down on the network support body 12. The pore structure that is connected up and down promotes the circulation of hot air flow, accelerates heat transfer and cooling during the sintering process, improves the accuracy of temperature control, and also improves the sintering efficiency, which helps to improve the internal organization uniformity and product quality of the sintered parts. The side support blocks 2 are arranged at intervals and the ends are flush. When the ceramic pads are stacked, they carry the surrounding edge 11 of the upper ceramic pad; a heat exchange gap 21 is formed between adjacent side support blocks 2. The side support blocks 2 are kept at a certain distance from each other, which can reduce the overall weight and facilitate heat exchange. The ends of the side support blocks 2 are flush, ensuring that the surrounding edge 11 of the upper ceramic mat can fall smoothly on the lower support block, facilitating the stacking of multiple ceramic mats to double the production efficiency and ensure the stability of the stacked multi-layer mats. Figure 4 The diagram shows two ceramic pads stacked together, but in actual use, there may be three, four or more. The gaps between adjacent support blocks form air passages, namely heat exchange gaps 21, which enhance the heat exchange effect and further improve the accuracy and efficiency of sintering temperature control.

[0030] Preferably, the network support body 12 includes an integrally connected central limiting ring 123 and a group of radiating support ribs 124; heat exchange holes 122 are formed in the central limiting ring 123 and between adjacent radiating support ribs 124. As a part of the network support body 12, the central limiting ring 123 plays a limiting role when sintering powder metallurgy gears, cams and other parts with a central boss. For parts with a central boss, the central limiting ring 123 provides an inner cavity that cooperates with the boss, so that the parts before sintering can be placed more accurately in the center of the ceramic pad, which can avoid problems such as uneven sintering and shape distortion caused by skewed or moved placement of parts, and improve the geometric accuracy of the parts and the consistency of performance of parts from different batches. In addition, the network support body 12 adopts an integrally connected central limiting ring 123 and radiating support rib 124 structure. The radial support ribs 124 are radiated outward from the central limiting ring 123, which not only reduces their own weight, but also forms a stable support skeleton that can withstand the weight of the parts and possible stress during the sintering process, ensuring the structural integrity and bearing capacity of the ceramic pad under high temperature conditions. The heat exchange holes 122 formed between adjacent radial support ribs 124 and inside the central limiting ring 123 constitute an efficient heat exchange network. These pores allow hot air to flow freely, which helps to quickly and evenly heat and cool the parts.

[0031] Preferably, in the network support body 12 , based on comprehensive considerations of structural stability, heat exchange efficiency, and process feasibility, 3 to 9 radial support ribs 124 , such as 5, 6, or 7 radial support ribs 124 , are radially connected from the central limiting ring 123 to the surrounding area.

[0032] For the bottom support platform, the area of ​​the area surrounded by the edge 11 is recorded as S0, and the cross-sectional area occupied by the heat exchange hole 122 is recorded as S1, S2,…, Sn. Preferably, (S1+S2+…+Sn) / S0=0.55~0.90. The area ratio is the ratio of the total area of ​​the heat exchange holes 122 to the total area of ​​the area surrounded by the edge 11. A higher area ratio means a higher porosity, which is conducive to the smoother passage of hot air through the pores during the sintering process, thereby enhancing the heat exchange effect. Although a higher porosity is conducive to heat exchange, excessive porosity will also weaken the structural strength and rigidity of the bottom support platform, affecting its durability, while also increasing the difficulty of manufacturing the ceramic pad and increasing the scrap rate. The area ratio in the range of 0.55~0.90 takes into account the structural stability and durability of the support platform while ensuring the heat exchange efficiency. Within this ratio range, the pore structure of the bottom support platform can effectively promote heat exchange without excessively weakening the overall strength.

[0033] Further preferably, (S1+S2+…+Sn) / S0=0.62~0.85.

[0034] As a further improvement, a first limiting step 22 is provided on the inner side of the top of the side support block 2, and a second limiting step 111 is provided on the bottom edge of the surrounding edge 11; when the ceramic pads are stacked, the second limiting step 111 of the upper ceramic pad is engaged with the first limiting step 22 of the lower ceramic pad. When the upper ceramic pad is placed on the lower ceramic pad, the second limiting step 111 of the upper ceramic pad will be aligned with the first limiting step 22 of the lower ceramic pad and engage with each other. This design ensures that each layer of ceramic pads can be accurately aligned in the vertical direction when stacked, avoiding unstable placement of sintered parts due to offset. Especially when placed in a mesh belt furnace for sintering, it can effectively prevent the stacked ceramic pads from tipping over due to mesh belt movement.

[0035] The surrounding edge 11 is preferably in the shape of a ring, and a continuous second limiting step 111 in the shape of a ring is formed along the bottom edge of the surrounding edge 11. The ring-shaped surrounding edge 11 makes the ceramic pad have a clear and regular circular boundary, which is convenient for the operator to intuitively judge and adjust the position of the ceramic pad in the horizontal direction. There is no need to adjust the angle during stacking, which makes the stacking process simpler and improves work efficiency. In addition, the ring-shaped surrounding edge 11 keeps the distance from the edge to the center of the ceramic pad consistent, which helps to form a more uniform heat exchange effect and improve the sintering quality.

[0036] Preferably, the side support blocks 2 are arranged at equal intervals along the peripheral edge 11, and the number of the side support blocks 2 is 3 to 9, which ensures the stacking stability of the ceramic pad while taking into account the manufacturing difficulty and manufacturing cost of the ceramic pad.

[0037] For the bottom support platform, the perimeter of the edge 11 is L0, and the perimeters occupied by the side support blocks 2 are L1, L2, ..., Ln, respectively, then (L1 + L2 + ... + Ln) / L0 = 0.35 ~ 0.70. This range is a balance range selected based on support stability and heat exchange efficiency, ensuring that the ceramic pad can provide stable support, ensure stacking stability, and take into account good heat exchange efficiency.

[0038] As a further improvement, for any i,j∈{1,2, …,n}, (Li-Lj) / Li=-0.05~0.05. That is to say, under the premise that the side support blocks 2 are arranged at equal intervals along the surrounding edge 11, the difference in the perimeter of any two adjacent side support blocks 2 is within the range of ±0.05%, so that the heat of the parts in all directions around can be roughly the same, and the temperature in all directions during the sintering process is more uniform, ensuring the sintering quality.

[0039] The above implementation modes are exemplary, and their purpose is to illustrate the technical concept and features of the utility model so that people familiar with the technology in this field can understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A ceramic pad for supporting a powder metallurgy sintered part, characterized in that: The invention is obtained by integrally molding ceramic materials, comprising a bottom support platform and a group of side support blocks (2) arranged around the outer periphery of the bottom support platform; the bottom support platform has an annular peripheral edge (11) and a network support body (12) connected to the area surrounded by the peripheral edge (11); the upper side of the network support body (12) has a flat bearing surface (121) for bearing the powder metallurgy sintered part, and a plurality of heat exchange holes (122) extending vertically are distributed on the network support body (12); the side support blocks (2) are arranged at intervals and the ends are flush with each other, and when the ceramic pads are stacked, they bear the peripheral edge (11) of the upper ceramic pad; and heat exchange gaps (21) are formed between adjacent side support blocks (2).

2. The ceramic pad for supporting a powder metallurgy sintered part according to claim 1, characterized in that: The network support body (12) comprises a central limiting ring (123) and a group of radiating supporting ribs (124) which are integrally connected; the heat exchange holes (122) are formed in the central limiting ring (123) and between adjacent radiating supporting ribs (124).

3. The ceramic pad for supporting a powder metallurgy sintered part according to claim 2, characterized in that: In the network support body (12), 3 to 9 radiating support ribs (124) are radiatedly connected from the central limiting ring (123) to the periphery.

4. The ceramic pad for supporting a powder metallurgy sintered part according to claim 2, characterized in that: The area of ​​the region enclosed by the surrounding edge (11) is S0, and the cross-sectional areas occupied by the heat exchange holes (122) are S1, S2, ..., Sn respectively, so (S1+S2+...+Sn) / S0=0.55~0.

90.

5. The ceramic pad for supporting a powder metallurgy sintered part according to claim 4, characterized in that: (S1+S2+…+Sn) / S0=0.62~0.

85.

6. The ceramic pad for supporting a powder metallurgy sintered part according to claim 1, characterized in that: A first limiting step (22) is provided on the inner side of the top of the side support block (2), and a second limiting step (111) is provided on the bottom edge of the surrounding edge (11); when the ceramic pads are stacked, the second limiting step (111) of the upper ceramic pad is engaged with the first limiting step (22) of the lower ceramic pad.

7. The ceramic pad for supporting a powder metallurgy sintered part according to claim 6, characterized in that: The surrounding edge (11) is in the shape of a circular ring, and a second limiting step (111) in the shape of a circular ring is formed along the bottom edge of the surrounding edge (11).

8. The ceramic pad for supporting a powder metallurgy sintered part according to claim 1, characterized in that: The surrounding edge (11) is in the shape of a ring, and the side support blocks (2) are arranged at equal intervals along the surrounding edge (11), and the number of the side support blocks (2) is 3 to 9.

9. The ceramic pad for supporting a powder metallurgy sintered part according to claim 8, characterized in that: The perimeter of the surrounding edge (11) is L0, and the perimeters occupied by the side support blocks (2) are L1, L2, ..., Ln respectively, so (L1+L2+...+Ln) / L0=0.35~0.

70.

10. The ceramic pad for supporting a powder metallurgy sintered part according to claim 9, characterized in that: For any i,j∈{1,2, …,n}, (Li-Lj) / Li=-0.05~0.05.

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