A method for integrally molding a spherical bearing

Abstract

This invention provides a method for integrally forming a spherical plain bearing, belonging to the field of spherical plain bearing manufacturing technology. Specifically, it includes: Step 1, determining the type and particle size of powder to be used for the spherical plain bearing based on the performance requirements of the bearing. Step 2, using the powder as raw material, filling the cavity in the inner ring mold, and pressing the inner ring blank of the spherical plain bearing. Step 3, spraying an intermediate layer onto the outer spherical surface of the inner ring blank. Step 4, placing the inner ring blank into the outer ring mold, filling the outer side of the inner ring blank with powder raw material, and pressing the outer ring blank of the spherical plain bearing to obtain an integral spherical plain bearing blank. Step 5, sintering the integral spherical plain bearing blank. Step 6, removing the intermediate layer between the inner and outer rings of the sintered spherical plain bearing and polishing all surfaces. This method does not involve plastic deformation processes and can be applied to raw materials with poor plasticity.

Description

Technical Field

[0001] This invention belongs to the field of spherical plain bearing manufacturing technology, and relates to a manufacturing method for integrally forming a spherical plain bearing. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Spherical plain bearings, also known as plain spherical bearings, mainly consist of an outer ring with an inner spherical surface and an inner ring with an outer spherical surface. Because spherical plain bearings can oscillate at any angle, they have advantages such as simple structure, small size, and high load-bearing capacity, and are widely used in agricultural machinery, aerospace, and automotive industries. However, due to the spherical mating surfaces of the inner and outer rings, and the fact that the widest part of the inner ring is larger than the opening size of the outer ring, assembling the inner and outer rings of a spherical plain bearing is quite difficult.

[0004] Currently, the commonly used solution is the unibody extrusion method, which involves placing an inner ring with an outer spherical surface into an outer ring whose inner and outer surfaces are machined into straight cylindrical surfaces. Extrusion then brings the inner surface of the outer ring into contact with the inner spherical surface of the inner ring, thus completing the assembly of the spherical plain bearing. However, this method suffers from difficulty in determining the extrusion force, making it challenging to improve control precision, and it cannot be used with materials exhibiting poor plasticity. Patent application (CN202010301655.8) proposes a split assembly method for the outer ring of a spherical plain bearing. This method divides the outer ring into an upper outer ring and a lower outer ring, which are then assembled sequentially onto the inner ring, and finally fixed together using a bearing sleeve. This method is not only complex in its process, but the outer ring is not a single-piece structure, and the gaps in the split structure affect the mechanical properties of the spherical plain bearing. Therefore, both the unibody extrusion method and the split assembly method have unresolved technical problems, leading to shortcomings in the manufacturing and performance of spherical plain bearings. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for manufacturing a single-piece spherical plain bearing, in which the inner and outer rings are sintered simultaneously, eliminating the need for plastic deformation or separate assembly, thus simplifying the bearing manufacturing process and improving bearing performance.

[0006] To achieve the above objectives, the manufacturing method of the integrally formed spherical bearing of the present invention includes:

[0007] Step 1: Determine the type and particle size of powder to be used for the inner and outer rings of the spherical plain bearing based on the performance requirements of the bearing.

[0008] Step 2: Using the powder from Step 1 as raw material, press the inner ring blank of the spherical bearing using an inner ring mold. The blank includes a through hole penetrating the upper and lower surfaces, and the side surface is an outer spherical surface.

[0009] Step 3: Spray an intermediate layer onto the outer spherical surface of the inner ring blank.

[0010] Step 4: Place the inner ring blank into the outer ring mold, fill the outside of the inner ring blank with powder raw material, and press the outer ring blank of the spherical bearing to obtain an integrated spherical bearing blank. The integrated spherical bearing blank includes an inner ring blank and an outer ring blank. The widest part of the inner ring blank is larger than the opening size of the outer ring blank. The outer spherical surface of the inner ring blank and the inner spherical surface of the outer ring blank form an intermediate layer.

[0011] Step 5: Sinter the integrated spherical bearing blank.

[0012] Step 6: Remove the intermediate layer between the inner and outer rings of the sintered spherical plain bearing and polish all surfaces to obtain the spherical plain bearing product.

[0013] The intermediate layer includes high-temperature resistant powder and binder, which can separate the inner and outer rings during the sintering process and prevent them from sticking together.

[0014] In step one, the powder can be ceramic material powder or metal material powder used in powder metallurgy processing.

[0015] The inner and outer rings of a spherical plain bearing can be made of the same material or different materials.

[0016] Secondly, a system for a manufacturing method of integrally forming spherical bearings.

[0017] The system includes an inner ring mold and an outer ring mold.

[0018] In the inner ring mold, the cavity formed by the inner ring center axis, the inner spherical surface of the upper inner ring mold, and the inner spherical surface of the lower inner ring mold is used to fill the powder raw material for forming the outer spherical surface of the bearing inner ring. The lower inner ring die is inserted between the inner ring center axis and the inner cylindrical surface of the upper inner ring mold, and the upper inner ring die is inserted between the inner ring center axis and the inner cylindrical surface of the lower inner ring mold. The lower inner ring die and the upper inner ring die are used for bidirectional extrusion forming of the inner ring blank.

[0019] In the outer ring die, the outer ring's central axis and the inner ring blank have the same bore diameter. The upper and lower outer ring dies have grooves with the same dimensions as the inner ring blank, used for positioning the inner ring blank horizontally. A positioning block is inserted between the outer ring's central axis and the cylindrical surface of the lower outer ring die for positioning the inner ring blank's height. The cavity formed by the upper and lower outer ring dies and the inner ring blank is filled with powder raw material for forming the bearing outer ring. The lower and upper outer ring dies are used for bidirectional extrusion forming of the outer ring blank.

[0020] Thirdly, the method of using the above-mentioned manufacturing method for integral molding of spherical bearings.

[0021] The method of using the inner ring mold is as follows: a bidirectional extrusion method is adopted, in which the powder in the inner ring mold is simultaneously extruded by the lower inner ring mold and the upper inner ring mold. As the extrusion time increases, the powder in the extrusion mold gradually forms an inner ring blank with a certain strength. After the inner ring mold is moved down to the central axis and the upper inner ring mold and the lower inner ring mold are taken out vertically upward, a pushing force is applied to the upper inner ring mold, and the inner ring blank is ejected from the lower inner ring mold by the upper inner ring mold.

[0022] The outer ring mold is used as follows: a bidirectional extrusion forming method is adopted, in which the powder in the inner cavity of the outer ring mold is simultaneously extruded by the upper and lower outer ring molds. As the extrusion time increases, the powder in the extrusion mold gradually forms an outer ring blank with a certain strength. After the outer ring is moved down to the center axis and the upper and lower outer ring molds are taken out vertically upward, a pushing force is applied to the positioning block and the upper outer ring mold. The positioning block is used to push the spherical bearing blank out of the lower outer ring mold.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. This invention enables the integral molding of spherical plain bearings, eliminating the need for separate assembly or processing of the inner and outer rings. This solves the problems of difficult assembly of spherical plain bearings and high scrap rates of traditional assembly methods, simplifies the spherical plain bearing process, and reduces the workload of manufacturing spherical plain bearings.

[0025] 2. The present invention uses an extrusion and sintering method (powder metallurgy), which is a near-forming process. The process parameters are easy to control and the control precision is high. Only a small amount of processing is needed to achieve high precision, which can save raw materials and reduce the processing cost of spherical bearings.

[0026] 3. The method of the present invention does not involve plastic deformation process and can be applied to raw materials with poor plasticity.

[0027] 4. Compared with traditional machining methods such as turning, it is easier to achieve mechanization and automation, which is conducive to the mechanized mass production of standard spherical bearing parts. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 This is a schematic diagram of the inner ring mold in a specific implementation.

[0030] Figure 2 This is a schematic diagram of steps two and three in a specific implementation method.

[0031] Figure 3 This is a schematic diagram of the outer ring mold in a specific implementation.

[0032] Figure 4 This is a schematic diagram of step four in a specific implementation method.

[0033] Figure 5 This is a schematic diagram of the integrated spherical bearing blank in a specific embodiment.

[0034] Figure 6 This is a structural schematic diagram of the spherical bearing product in a specific implementation.

[0035] Among them, 1. Inner ring aligned with the central axis; 2. Inner ring upper mold; 3. Inner ring lower mold; 4. Inner ring upper pressing mold; 5. Inner ring lower pressing mold; 6. Outer ring aligned with the central axis; 7. Outer ring upper mold; 8. Outer ring lower mold; 9. Positioning block; 10. Outer ring upper pressing mold; 11. Outer ring lower pressing mold; 12. Outer ring blank; 13. Inner ring blank; 14. Intermediate layer; 15. Bearing inner ring; 16. Bearing outer ring. Detailed Implementation

[0036] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, 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.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] Example 1: A method for manufacturing a spherical plain bearing in one piece, comprising:

[0039] Step 1: Determine the type and particle size of powder to be used for the inner and outer rings of the spherical plain bearing based on the performance requirements of the bearing.

[0040] The powder can be selected as ceramic material powder, including one or more of silicon nitride powder, silicon carbide powder, and alumina powder.

[0041] The powder can also be selected from metal material powders used in powder metallurgy processing, including one or more of iron-based powders, copper-based powders, and aluminum-based powders.

[0042] The inner and outer rings of a spherical plain bearing can be made of the same material or different materials.

[0043] In this embodiment, the powders filling the inner and outer rings are all mixed powders that are uniformly mixed from Si3N4 powder (particle size between 0.1-20μm), Y2O3 powder (particle size between 1-10μm) and Al2O3 powder (particle size between 1-10μm) and then sieved through a 100-mesh sieve.

[0044] Step two: Using the mixed powder from step one as raw material, press the inner ring blank 13 of the spherical bearing using an inner ring mold. The inner ring blank 13 includes a through hole penetrating the upper and lower surfaces, and its side surface is an outer spherical surface, such as... Figure 5 .

[0045] Step 3: Spray a layer of intermediate layer 14 of a certain thickness onto the outer spherical surface of the inner ring blank 13, such as... Figure 5 .

[0046] The middle layer is a uniform mixture of high-temperature resistant powder and binder, which can separate the inner and outer rings during sintering and prevent them from sticking together.

[0047] Preferably, the high-temperature resistant powder can be nano-scale graphite powder, and the binder can be polypropylene. The two are uniformly mixed at 200°C to become the raw material for the intermediate layer, and sprayed under heated temperature conditions.

[0048] Preferably, the mass fraction of polypropylene can be between 10% and 50%.

[0049] The formula for determining the thickness of the intermediate layer is:

[0050]

[0051] In the formula, h: thickness of the intermediate layer; d1: outer ball diameter of the inner ring of the designed spherical plain bearing; S1: dimensional change rate of the inner ring material of the spherical plain bearing; D2: inner ball diameter of the outer ring of the designed spherical plain bearing; S2: dimensional change rate of the outer ring material of the spherical plain bearing.

[0052] Step four: Place the inner ring blank 13 into the outer ring mold, fill the outside of the inner ring blank 13 with the mixed powder from step one, and press the outer ring blank 12 of the spherical plain bearing to obtain an integrated spherical plain bearing blank. The integrated spherical plain bearing blank includes the inner ring blank 13 and the outer ring blank 12. The widest part of the inner ring blank 12 is larger than the opening size of the outer ring blank 13. The outer spherical surface of the inner ring blank 13 and the inner spherical surface of the outer ring blank 12 form an intermediate layer 14. Figure 5 .

[0053] Step 5: Sinter the integrated spherical plain bearing blank. Place the spherical plain bearing blank into the sintering furnace. The inner and outer ring powders go through the process of grain rearrangement, dissolution and precipitation of fine grains, and volume diffusion in sequence. After reaching the required density, the furnace temperature can be reduced back to room temperature to complete the sintering of the spherical plain bearing blank.

[0054] Step six: Remove the intermediate layer 14 between the inner and outer rings of the sintered spherical plain bearing, and polish all surfaces to obtain the spherical plain bearing product, such as... Figure 6 The inner ring 15 of the bearing can rotate within the outer ring 16 of the bearing, and the widest part of the inner ring 15 is larger than the opening size of the outer ring 16 of the bearing.

[0055] In steps two and four, the formula for determining the pressing amount of the die is:

[0056]

[0057] In the formula, H: downward pressure; Fill height; Loose packing density; : Density of the pressed blank.

[0058] Since the decomposition temperature of polypropylene and the melting point of graphite are around 400℃ and 3600℃ respectively, and the sintering temperature of most spherical plain bearing inner and outer ring materials is much greater than 400℃ and much less than 3600℃, such as iron-copper alloys at around 1200℃; the silicon nitride ceramic used in this embodiment has a sintering temperature of around 1800℃, when the sintering of the spherical plain bearing is completed, the polypropylene in the middle layer decomposes at high temperature, leaving only unreacted graphite powder. At this time, the powder in the middle layer is very easy to remove because there is no binder. Therefore, most of the middle layer can be removed manually and by rinsing with water. Since graphite does not react with water, the removed graphite powder can be collected and reused.

[0059] The present invention also relates to a system for a manufacturing method of integral forming of spherical bearings and a method of using the system.

[0060] like Figure 1 The cavity formed by the inner ring of the inner ring die, the inner ring center shaft 1, the inner ring upper die 2, and the inner ring lower die 3 is used to fill the powder raw material for forming the outer spherical surface of the bearing inner ring. The inner ring lower die 5 is inserted between the inner ring center shaft 1 and the inner ring upper die 2, and the inner ring upper die 4 is inserted between the inner ring center shaft 1 and the inner ring lower die 3. The inner ring lower die 5 and the inner ring upper die 4 are used for bidirectional extrusion forming of the inner ring blank.

[0061] like Figure 2The powder in the inner ring mold is extruded simultaneously by the inner ring lower die 4 and the inner ring upper die 5. As the extrusion time increases, the powder in the extrusion mold gradually forms an inner ring blank 13 with a certain strength. After the inner ring mold is moved down to the central axis 1 and the inner ring upper die 2 and the inner ring lower die 5 are taken out vertically upward, a pushing force is applied to the inner ring upper die 4, and the inner ring blank 13 is ejected from the inner ring lower die by the inner ring upper die 4.

[0062] like Figure 3 The outer ring of the outer ring die has the same hole diameter as the central shaft 6 and the inner ring blank 13. The outer ring upper die 10 and the outer ring lower die 11 have grooves with the same outer dimensions as the inner ring blank 13. These grooves are used to position the inner ring blank 13 in a horizontal position. A positioning block 9 is inserted between the cylindrical surface of the outer ring central shaft 6 and the outer ring upper die 10 for positioning the height of the inner ring blank 13. The cavity formed by the outer ring upper die 7, the outer ring lower die 8 and the inner ring blank 13 is used to fill powder raw materials for forming the bearing outer ring. The outer ring lower die 11 and the outer ring upper die 10 are used for bidirectional extrusion forming of the outer ring blank 12.

[0063] like Figure 4 The outer ring is formed by bidirectional extrusion molding, where the powder in the inner cavity of the outer ring mold is simultaneously extruded by the outer ring upper die 10 and the outer ring lower die 11. As the extrusion time increases, the powder in the extrusion mold gradually forms an outer ring blank 12 with a certain strength. After the outer ring center axis 6 is moved down and the outer ring upper die 7 and the outer ring lower die 11 are taken out vertically upward, a pushing force is applied to the positioning block 9 and the outer ring upper die 10. The positioning block 9 is used to push the spherical bearing blank out of the outer ring lower die 8.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A manufacturing method of an integrated knuckle bearing, characterized by, The application relates to a manufacturing method of a joint bearing integrally formed. Step one: determining the powder type and particle size of the inner and outer rings of the joint bearing according to the performance requirements of the joint bearing; Step two: using the powder in step one as raw material, pressing the inner ring compact of the joint bearing by using an inner ring die, the inner ring compact comprising a through hole penetrating through the upper and lower surfaces and the side surface being an outer spherical surface; Step three: spraying an intermediate layer on the outer spherical surface of the inner ring compact; Step four: placing the inner ring compact into an outer ring die, filling the powder raw material outside the inner ring compact, pressing the outer ring compact of the joint bearing, and obtaining an integrated joint bearing compact; The integrated joint bearing compact comprises the inner ring compact and the outer ring compact, the widest part of the inner ring compact is larger than the opening size of the outer ring compact, and the intermediate layer is between the outer spherical surface of the inner ring compact and the inner spherical surface of the outer ring compact; Step five: sintering the integrated joint bearing compact; Step six: removing the intermediate layer between the inner and outer rings of the joint bearing after sintering and polishing each surface to obtain a joint bearing product; The intermediate layer comprises high-temperature-resistant powder and an adhesive and can separate the inner and outer rings during the sintering process to prevent the inner and outer rings from being bonded. The thickness determination formula of the intermediate layer is as follows: h=S1*d1-S2*D2 wherein h is the thickness of the intermediate layer, d1 is the designed outer spherical diameter of the inner ring of the joint bearing, S1 is the size change rate of the material of the inner ring of the joint bearing, D2 is the designed inner spherical diameter of the outer ring of the joint bearing, and S2 is the size change rate of the material of the outer ring of the joint bearing. The determination formula of the pressing amount of the die is as follows: h=S1*d1-S2*D2.

2. The manufacturing method of the joint bearing integrally formed according to claim 1, wherein In step one, the powder is ceramic material powder or metal material powder for powder metallurgy processing. In the formula, H: amount of depression; : filling height; : bulk density; : density of the compact. The powder is mixed Si3N4 powder with a particle size of 0.1-20 mu m, Y2O3 powder with a particle size of 1-10 mu m and Al2O3 powder with a particle size of 1-10 mu m, and the mixed powder is obtained after being screened through a 100-mesh sieve. The materials of the inner and outer rings are the same or different.

3. The method of manufacturing a knuckle bearing integrally formed as claimed in claim 2, wherein, 5. The manufacturing method of the joint bearing integrally formed according to claim 1, wherein 4. The method of manufacturing a knuckle bearing unit of claim 1, wherein In step three, the high-temperature-resistant powder is nanoscale graphite powder, and the adhesive is polypropylene, and the two are uniformly mixed at 200 DEG C to become the intermediate layer raw material.

6. A joint bearing manufactured by using the manufacturing method of the joint bearing integrally formed according to any one of claims 1-5. The inner ring die and the outer ring die are included. In the inner ring die, the inner ring centering shaft, the inner spherical surface of the upper inner ring die and the inner spherical surface of the lower inner ring die form a cavity, the inner ring centering shaft and the inner cylindrical surface of the upper inner ring die are inserted with an inner ring lower pressing die, the inner ring centering shaft and the inner cylindrical surface of the lower inner ring die are inserted with an inner ring upper pressing die, and the inner ring lower pressing die and the inner ring upper pressing die are used for bidirectional extrusion forming of the inner ring compact.

7. A system for the integrated forming manufacturing method of a knuckle bearing according to any one of claims 1 to 5, characterized in that, ​ 8. The system for manufacturing a unitarily formed joint bearing of claim 7, wherein, ​ 9. The system for manufacturing a unitarily formed joint bearing of claim 7, wherein, In the outer ring die, the outer ring centering shaft has the same hole diameter as the inner ring compact, the outer ring upper and lower dies have grooves with the same size as the outer shape of the inner ring compact, the grooves are used for positioning the horizontal position of the inner ring compact, a positioning block is inserted between the outer ring centering shaft and the cylindrical surface of the outer ring lower die, which is used for positioning the height position of the inner ring compact, the outer ring upper and lower dies and the inner ring compact form a cavity, and the outer ring lower and upper dies are used for bidirectional extrusion forming of the outer ring compact.

10. A method of using a system for manufacturing a knitted joint bearing according to any one of claims 8-9, characterized in that, The use method of the inner ring die is as follows: the inner ring lower and upper dies are used to simultaneously extrude the powder in the inner ring die by bidirectional extrusion, with the increase of the extrusion time, the powder in the extrusion die gradually forms an inner ring compact with certain strength, the inner ring centering shaft is moved downward, the inner ring upper and lower dies are vertically taken out upward, a pushing force is applied to the inner ring upper die, and the inner ring compact is pushed out of the inner ring lower die by the inner ring upper die.

11. The method of using a system for manufacturing a knuckle bearing unitary forming manufacturing method according to claim 10, wherein, The use method of the outer ring die is as follows: the outer ring upper and lower dies are used to simultaneously extrude the powder in the inner cavity of the outer ring die by bidirectional extrusion forming, with the increase of the extrusion time, the powder in the extrusion die gradually forms an outer ring compact with certain strength, the outer ring centering shaft is moved downward, the outer ring upper and lower dies are vertically taken out upward, a pushing force is applied to the positioning block and the outer ring upper die, and the outer ring compact is pushed out of the outer ring lower die by the positioning block.

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