A method for producing self-lubricating bearings

Abstract

This invention relates to the field of bearing technology and proposes a method for producing self-lubricating bearings, comprising the following steps: S1, preparing pre-impregnated yarn sheets for the inner liner and support layers; S2, winding and forming; S3, curing the pre-impregnated yarn to obtain a self-lubricating bearing blank; S4, machining the self-lubricating bearing blank to obtain a self-lubricating bearing, wherein the curing pressure is 0.3MPa~1.2MPa. This technical solution solves the problems of low production efficiency, high void content, low strength, and inconsistent quality of self-lubricating bearings in related technologies.

Description

Technical Field

[0001] This invention relates to the field of bearing technology, and more specifically, to a method for producing a self-lubricating bearing. Background Technology

[0002] To meet the demand for low-wear, high-load self-lubricating bearings, engineers have developed a series of reinforced fiber bearings. Compared with other types of self-lubricating bearings, fiber-wound bearings have irreplaceable advantages, such as extremely low coefficient of friction, higher load capacity, better corrosion resistance, excellent dimensional stability, higher operating temperature, lower coefficient of thermal expansion, and lightweight. With the continuous expansion of application scenarios, higher requirements are being placed on the overall performance of fiber-wound bearings.

[0003] Currently, in the process of manufacturing self-lubricating bearings, engineers usually use wet winding and curing oven curing. Although this method is simple and does not require high-end equipment, it has low production efficiency, a harsh production environment, and the products have high porosity, low strength, and poor quality uniformity. Summary of the Invention

[0004] This invention proposes a method for producing self-lubricating bearings, which solves the problems of low production efficiency, high void content, low strength, and uneven quality of self-lubricating bearings in related technologies.

[0005] The technical solution of the present invention is as follows:

[0006] A method for producing a self-lubricating bearing includes the following steps: curing pre-impregnated yarn to obtain a self-lubricating bearing, wherein the curing pressure is 0.15 MPa to 1.2 MPa.

[0007] As a further technical solution, the curing pressure is 0.8 MPa.

[0008] As a further technical solution, the curing temperature is 180℃~200℃.

[0009] As a further technical solution, pressure is applied during the curing process, and the viscosity of the resin during the pressure application is 10 Pa·s to 40 Pa·s.

[0010] As a further technical solution, the curing is carried out under vacuum and pressure in an autoclave, and the encapsulation is performed using a combination of "porous release membrane + adhesive-absorbing felt + non-porous release membrane + air-guiding felt + vacuum bag". The amount of adhesive-absorbing felt used is calculated, and the calculation formula is as follows:

[0011]

[0012] Where: N—the number of layers of absorbent pad to be placed;

[0013] ρ f —Linear density of dry yarn, g / m;

[0014] ρ m —Linear density of the prepreg yarn, g / m;

[0015] W f —Design mass fraction of fiber in the product, %

[0016] d—Diameter of the core mold, mm;

[0017] D—Outer diameter of the product after winding, in mm;

[0018] M s —Theoretical adhesive absorption capacity of a single layer of absorbent felt (measured experimentally), g / cm³ 2 ;

[0019] ξ—Correction coefficient (0.6~1, derived empirically).

[0020] This invention uses a vacuum pressurization method in an autoclave to cure and mold the product. The design of the adhesive absorption scheme can more accurately control the fiber volume content of the product to 60%±5%, and the use of an integral bag-making method improves the packaging efficiency. According to the design and calculation results, a certain number of adhesive absorption layers are placed to obtain a product with controllable resin content, high quality, and low porosity.

[0021] As a further technical solution, the method for preparing the prepreg yarn includes the following steps: depositing filler on the surface of the impregnated fiber bundle and baking it at 70℃~90℃ for 5min~20min to obtain the prepreg yarn.

[0022] Compared to traditional wet winding processes, this invention employs a "semi-dry" method for preparing prepreg yarn. The resin in the yarn is baked at 70℃~90℃ for 5-20 minutes to remove volatile components and allow the resin to gel to a certain degree, after which it can be wound and stored. This method ensures a clean operating environment during the winding process and allows for higher winding speeds, significantly improving production efficiency. It also further reduces the void content of self-lubricating bearings and further enhances their strength.

[0023] As a further technical solution, before the deposition of the filler, the process includes extrusion and scraping of adhesive, and the adhesive content is controlled by extrusion and scraping to make the fiber volume content in the prepreg yarn 45%~60%.

[0024] As a further technical solution, the deposited filler is specifically deposited by electrostatic powder spraying during the fiber bundle traction process after impregnation. The electrostatic voltage during electrostatic powder spraying is 30kV~70kV, the powder supply pressure is 0.15MPa~0.3MPa, and the spraying distance is 200mm~500mm. The traction speed is 0.1~1m / s.

[0025] The electrostatic powder spraying process in this invention is equipped with a powder recovery device, with a recovery rate of ≥80%.

[0026] This invention uses electrostatic powder spraying to uniformly settle filler into the resin on the surface of the yarn, ensuring an ideal distribution of the filler. This solves the problems of uneven dispersion and agglomeration of filler in the resin due to sedimentation. By controlling the electrostatic voltage to 30kV~70kV, the powder supply air pressure to 0.15MPa~0.3MPa, the spraying distance to 200mm~500mm, and the traction speed to 0.1~1m / s, the filler content in the prepreg yarn is controlled to be 5%~25% of the resin matrix mass content, ensuring quality uniformity, further reducing the void content of the self-lubricating bearing, and further improving the strength.

[0027] In this invention, the resin matrix refers to the sum of epoxy resin, curing agent, accelerator, coupling agent and diluent.

[0028] As a further technical solution, the adhesive solution for impregnation includes the following raw materials in parts by weight: 60-120 parts epoxy resin, 40-105 parts curing agent, 1-5 parts accelerator, and 5-30 parts additives.

[0029] As a further technical solution, the additives include 2-10 parts of coupling agent, 1-10 parts of diluent, and 2-10 parts of solvent.

[0030] As a further technical solution, the preparation method of the adhesive includes the following steps: mixing epoxy resin, diluent and solvent, then adding the remaining components and mixing evenly to obtain the adhesive.

[0031] As a further technical solution, after mixing evenly, vacuum is applied to remove bubbles, and the vacuuming time is 10~30 minutes.

[0032] As a further technical solution, the curing agent is an acid anhydride-based latent curing agent.

[0033] As a further technical solution, the anhydride-based latent curing agent includes methylhexahydrophthalic anhydride and / or methylnadic anhydride.

[0034] As a further technical solution, the accelerator includes one or more of tertiary amine salt complexes, Lewis acid complexes, and imidazole accelerators.

[0035] As a further technical solution, the coupling agent is a silane coupling agent, such as one or more of KH550, KH560, and KH570, preferably KH550.

[0036] As a further technical solution, the diluent includes one or more of ethylene glycol diglycidyl ether, phenyl glycidyl ether, and diglycidyl ether.

[0037] As a further technical solution, the solvent includes acetone and / or ethanol.

[0038] As a further technical solution, the prepreg yarn includes, from the inside out, an inner lining prepreg yarn and a support layer prepreg yarn. The raw materials of the inner lining prepreg yarn include polyester fiber and PTFE fiber, and the raw materials of the support layer prepreg yarn include one or more of alkali-free glass fiber, basalt fiber, carbon fiber, and high-silica glass fiber cloth.

[0039] As a further technical solution, the mass ratio of the polyester fiber to the PTFE fiber is 30~70:20~50.

[0040] As a further technical solution, the fiber fineness of the prepreg yarn in the inner lining layer is 400D~1000D, and the fiber fineness of the prepreg yarn in the support layer is 1500tex~3000tex.

[0041] As a further technical solution, the raw materials of the prepreg yarn of the inner lining layer also include 0-30 parts of aramid fiber and 0-30 parts of ultra-high molecular weight polyethylene fiber.

[0042] As a further technical solution, when the raw material of the prepreg yarn of the inner lining layer includes aramid fiber, the fineness of the aramid fiber is 200 tex.

[0043] In this invention, the fibers in the prepreg yarn of the inner lining layer can be continuous multifilament fibers, or multiple fibers can be woven into a woven tape using textile processes.

[0044] As a further technical solution, the epoxy resin includes 60-100 parts of bisphenol A type epoxy resin, 0-60 parts of bisphenol F type epoxy resin, and 0-20 parts of phenolic epoxy resin.

[0045] As a further technical solution, the bisphenol A type epoxy resin includes one or more of Dow DER332 type epoxy resin, 128 type epoxy resin, and E51 type epoxy resin.

[0046] As a further technical solution, the bisphenol F type epoxy resin includes one or two of NPEF170 type epoxy resin and NPEF-164X type epoxy resin.

[0047] As a further technical solution, the phenolic epoxy resin includes phenolic epoxy resin 638S and / or phenolic epoxy resin F51.

[0048] As a further technical solution, the filler includes one or more of PTFE powder, graphite powder, BN powder, MoS2, and carbon black.

[0049] As a further technical solution, the particle size of the filler is 10μm~100μm.

[0050] As a further technical solution, the method for producing a self-lubricating bearing includes the following steps: sequentially winding inner lining prepreg yarn and support prepreg yarn onto a mandrel, curing, and obtaining a self-lubricating bearing, wherein the curing pressure is 0.3MPa~1.2MPa.

[0051] In this invention, a four-dimensional winding machine is used to wind the product. The winding tension is selected according to the "equal torque" method, that is, the winding tension decreases step by step as the winding diameter increases, and the product is a constant value.

[0052] As a further technical solution, during the winding process, the yarn separation tension of the inner lining prepreg yarn and the support layer prepreg yarn are each independently 5N~20N, the ply tension is each independently 30N~200N, and the yarn exit speed is each independently 0.2m / s~2m / s.

[0053] As a further technical solution, the winding thickness of the prepreg yarn in the inner lining layer is 0.5~1mm, and the winding thickness of the prepreg yarn in the support layer is 3~5mm.

[0054] As a further technical solution, the cured process also includes demolding and machining, specifically: outer diameter machining, demolding and cutting.

[0055] As a further technical solution, the outer diameter machining is performed by grinding, the coolant is water-based, the single feed rate is ≤1mm, and the single feed rate for the last 2mm margin is ≤0.5mm; the cutting process is performed axially using a wire cutting device, and the coolant is water-based.

[0056] This invention uses a machining method of "grinding + water-based coolant" to control the feed rate and reduce damage to materials during processing.

[0057] The working principle and beneficial effects of this invention are as follows:

[0058] This invention provides a method for producing a self-lubricating bearing, comprising: curing pre-impregnated yarn to obtain a self-lubricating bearing; by controlling the pressure during the curing process to be 0.3MPa~1.2MPa, the void content of the self-lubricating bearing is reduced and the strength is improved. Attached Figure Description

[0059] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0060] Figure 1 This is a flowchart illustrating the manufacturing process of the prepreg yarn of this invention.

[0061] Figure 2 This is a flowchart illustrating the manufacturing process of the self-lubricating bearing of this invention. Detailed Implementation

[0062] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0063] Example 1

[0064] S1. The process flow chart for the production of prepreg yarn is as follows: Figure 1 As shown, it includes the following steps:

[0065] S11. Mix 60 parts of Dow DER332 epoxy resin, 20 parts of NPEL170 epoxy resin, 20 parts of phenolic epoxy resin 638S, 5 parts of ethylene glycol diglycidyl ether, and 5 parts of acetone at 60°C until homogeneous. After stirring for 25 minutes, add 70 parts of curing agent MHHPA, 2 parts of 2-ethyl-4-methylimidazole, and 3.5 parts of KH550. Continue stirring for 20 minutes until homogeneous. Then, vacuum for 30 minutes to remove bubbles and transfer the mixture to an impregnation tank.

[0066] S12. Yarn Preparation: The inner lining layer consists of 70 parts polyester fiber yarn (1000D fineness) and 30 parts PTFE fiber yarn (400D fineness); the filler consists of PTFE powder (50μm), graphite powder (10μm flakes), and MoS2 powder (10μm) in a mass ratio of 1:1:1; the support layer fiber is alkali-free glass fiber yarn (linear density 2000tex); the filler is carbon black (N330).

[0067] S13. Hang the above fibers on a yarn rack. Prepare the inner lining layer and support layer yarns separately using the same method. First, draw the fiber bundle tension to the impregnation system. After impregnation, control the glue content through an extrusion and scraping device. Calculate and control the fiber volume content to 50% (solvent removal). Continue traction through the powder spraying box for electrostatic powder spraying. The powder spraying gun deposits filler into the resin on the yarn surface. Excess filler is recycled through a recovery device. The electrostatic voltage is 50kV, the powder supply pressure is 0.2MPa, the spraying distance is 350mm, and the traction speed is 0.3m / s. The heating equipment bakes at 50℃ for 12 minutes to remove certain solvents and low-volatile substances, and the resin reaches a certain degree of gelation before yarn collection and storage. PTFE powder accounts for 5% of the resin matrix mass, graphite powder accounts for 5% of the resin matrix mass, MoS2 powder accounts for 5% of the resin matrix mass, and carbon black accounts for 5% of the resin matrix mass. The resin matrix refers to the sum of Dow DER332 epoxy resin, NPEL170 epoxy resin, phenolic epoxy resin 638S, ethylene glycol diglycidyl ether, curing agent MHHPA, 2-ethyl-4-methylimidazole, and KH550.

[0068] S2. The manufacturing process of self-lubricating bearings is shown in the flowchart below. Figure 2 As shown, it includes the following steps:

[0069] S21. Core mold processing and installation: After grinding and cleaning the core mold, apply two coats of release agent and let it dry. Then install it onto the winding machine and adjust the position of the core mold.

[0070] S22. Inner lining layer winding: A four-dimensional winding machine is used for winding. The winding tension is selected according to the "equal torque" rule, that is, the winding tension decreases step by step as the winding diameter increases, and the product is a constant value. The inner lining layer yarn sheet prepared above is used for winding. The yarn splitting tension is 10N~15N, the ply tension is 60N~150N, the yarn output speed is 1.2m / s, and the winding thickness is 0.8mm.

[0071] S23. Support layer winding and forming: The support layer yarn sheet prepared above is wound and formed, following the "equal torque" rule, with the yarn splitting tension being 5N~10N, the ply tension being 60N~150N, the yarn output speed being 1.2m / s, and the winding thickness being 4mm.

[0072] S24. Overall bag sealing and autoclave curing: After winding, the product is cured in an autoclave at 200℃ and 0.2MPa. The viscosity of the resin under pressure is 25Pa·s. The product is sealed using a combination of "porous release film + absorbent felt + non-porous release film + air-conducting felt + vacuum bag". The amount of absorbent felt used is calculated using the following formula:

[0073]

[0074] Where: N—the number of layers of absorbent pad to be placed;

[0075] ρ f —Linear density of dry yarn, g / m;

[0076] ρ m —Linear density of the prepreg yarn, g / m;

[0077] W f —Design mass fraction of fiber in the product, %

[0078] d—Diameter of the core mold, mm;

[0079] D—Outer diameter of the product after winding, in mm;

[0080] M s —Theoretical adhesive absorption capacity of a single layer of absorbent felt (measured experimentally), g / cm³ 2 ;

[0081] ξ—Correction coefficient (0.85).

[0082] S25. Demolding and Machining: After the product has cured, demolding and machining are performed in the following order: outer diameter machining → demolding → cutting. The outer diameter of the product is machined by grinding, and water-based coolant is used. The single feed rate during machining is 1mm, and the single feed rate for the last 2mm margin is 0.5mm. The cutting is performed axially using a wire cutting device, and water-based coolant is used to obtain a self-lubricating bearing.

[0083] Example 2

[0084] S1. The process flow chart for the production of prepreg yarn is as follows: Figure 1 As shown, it includes the following steps:

[0085] S10. Mix 100 parts of type 128 epoxy resin, 1 part of phenyl glycidyl ether, and 2 parts of ethanol at 60°C until homogeneous. After stirring for 25 minutes, add 70 parts of curing agent MHHPA, 2 parts of 2-ethyl-4-methylimidazole, and 2 parts of KH560. Continue stirring for 20 minutes until homogeneous. Then, vacuum for 20 minutes to remove bubbles and transfer the mixture to an impregnation tank.

[0086] S11. Yarn Preparation: The inner lining layer consists of 70 parts polyester fiber yarn (1000D fineness), 30 parts PTFE fiber (400D fineness), and 20 parts aramid fiber (200tex fineness); the filler consists of BN powder (100μm), carbon black (N330), and MoS2 powder (10μm) in a mass ratio of 1:1:1; the support layer fiber is carbon fiber (T700-12K); the filler is MoS2 powder (10μm).

[0087] S12. Hang the above fibers on a yarn rack. Prepare the inner lining layer and support layer yarns separately using the same method. First, draw the fiber bundle tension to the impregnation system. After impregnation, control the glue content through an extrusion and scraping device. Calculate and control the fiber volume content to 45% (solvent removal). Continue traction through the powder spraying box for electrostatic powder spraying. The powder spraying gun deposits filler into the resin on the yarn surface. Excess filler is recycled through a recovery device. The electrostatic voltage is 50kV, the powder supply pressure is 0.15MPa, and the spraying distance is 350mm. The traction speed is 0.25m / s. After being heated at 50℃ for 5 minutes, a certain amount of solvent and low-volatile substances are removed, and the resin reaches a certain degree of gelation. Then, the yarn is collected and stored. BN powder accounts for 5% of the resin matrix mass, carbon black accounts for 5% of the resin matrix mass, MoS2 powder accounts for 5% of the resin matrix mass, and MoS2 powder accounts for 5% of the resin matrix mass. The resin matrix refers to the sum of type 128 epoxy resin, phenyl glycidyl ether, curing agent MHHPA, 2-ethyl-4-methylimidazole and KH560.

[0088] S2. The manufacturing process of self-lubricating bearings is shown in the flowchart below. Figure 2 As shown, it includes the following steps:

[0089] S21. Core mold processing and installation: After grinding and cleaning the core mold, apply two coats of release agent and let it dry. Then install it onto the winding machine and adjust the position of the core mold.

[0090] S22. Inner lining layer winding: A four-dimensional winding machine is used for winding. The winding tension is selected according to the "equal torque" rule, that is, the winding tension decreases step by step as the winding diameter increases, and the product is a constant value. The inner lining layer yarn sheet prepared above is used for winding. The yarn splitting tension is 10N~15N, the ply tension is 50~100N, the yarn output speed is 0.2m / s, and the winding thickness is 0.5mm.

[0091] S23. Support layer winding and forming: The support layer yarn sheet prepared above is wound and formed, following the "equal torque" rule, with the yarn splitting tension being 5N~10N, the ply tension being 50~100N, the yarn exiting speed being 0.2m / s, and the winding thickness being 3mm.

[0092] S24. Overall bag sealing and autoclave curing: After winding, the product is cured in an autoclave at 190℃ and 0.15MPa. The viscosity of the resin under pressure is 10Pa·s. The product is sealed using a combination of "porous release film + absorbent felt + non-porous release film + air-conducting felt + vacuum bag". The amount of absorbent felt used is calculated, and the calculation formula is as follows:

[0093]

[0094] Where: N—the number of layers of absorbent pad to be placed;

[0095] ρ f —Linear density of dry yarn, g / m;

[0096] ρ m —Linear density of the prepreg yarn, g / m;

[0097] W f —Design mass fraction of fiber in the product, %

[0098] d—Diameter of the core mold, mm;

[0099] D—Outer diameter of the product after winding, in mm;

[0100] M s —Theoretical adhesive absorption capacity of a single layer of absorbent felt (measured experimentally), g / cm³ 2 ;

[0101] ξ — Correction coefficient (0.6).

[0102] S25. Demolding and Machining: After the product has cured, demolding and machining are performed in the following order: outer diameter machining → demolding → cutting. The outer diameter of the product is machined by grinding, and water-based coolant is used. The single feed rate during machining is 1mm, and the single feed rate for the last 2mm margin is 0.5mm. The cutting is performed axially using a wire cutting device, and water-based coolant is used to obtain a self-lubricating bearing.

[0103] Example 3

[0104] S1. The process flow chart for the production of prepreg yarn is as follows: Figure 1 As shown, it includes the following steps:

[0105] S11. Mix 60 parts of E51 epoxy resin, 60 parts of NPEF-164X epoxy resin, 10 parts of ethylene glycol diglycidyl ether, and 10 parts of acetone at 60℃ until homogeneous. After stirring for 25 minutes, add 102 parts of curing agent MNA, 3 parts of 2-ethyl-4-methylimidazole, and 10 parts of KH570. Continue stirring for 20 minutes until homogeneous. Then, vacuum for 10 minutes to remove bubbles and transfer the mixture to an impregnation tank.

[0106] S12. Yarn Preparation: The inner lining fiber consists of 70 parts polyester fiber yarn (1000D fineness), 30 parts PTFE fiber (400D fineness), and 20 parts ultra-high molecular weight polyethylene fiber (400D fineness); the filler consists of BN powder (100μm), carbon black (N330), and MoS2 powder (10μm) in a mass ratio of 1:1:1; the support layer fiber is basalt fiber (2400tex fineness); the filler is MoS2 powder (10μm).

[0107] S13. Hang the above fibers on the yarn frame. Prepare the inner lining layer and the support layer yarn sheets separately using the same preparation method. First, draw the fiber bundle tension to the impregnation system. After impregnation, control the glue content through the extrusion and scraping devices. Calculate and control the fiber volume content to 60% (to remove solvent). Continue to pull the fiber bundle through the powder spraying box for electrostatic powder spraying. The powder spraying gun deposits the filler into the resin on the surface of the yarn sheet. Excess filler is recycled back into the cycle through the recovery device. The electrostatic voltage is 70kV, the powder supply air pressure is 0.3MPa, the spraying distance is 500mm, and the traction speed is 0. 15m / s, after being heated at 50℃ for 20 minutes to remove certain solvents and low-volatile substances, and the resin reaches a certain degree of gelation, it is then collected and stored. BN powder accounts for 5% of the resin matrix mass, carbon black accounts for 5% of the resin matrix mass, MoS2 powder accounts for 5% of the resin matrix mass, and the resin matrix refers to the sum of E51 type epoxy resin, NPEF-164X type epoxy resin, ethylene glycol diglycidyl ether, curing agent MNA, 2-ethyl-4-methylimidazolium and KH570;

[0108] S2. The manufacturing process of self-lubricating bearings is shown in the flowchart below. Figure 2 As shown, it includes the following steps:

[0109] S21. Core mold processing and installation: After grinding and cleaning the core mold, apply two coats of release agent and let it dry. Then install it onto the winding machine and adjust the position of the core mold.

[0110] S22. Inner lining layer winding: The winding is carried out using a four-dimensional winding machine. The winding tension is selected according to the "equal torque" rule, that is, the winding tension decreases step by step as the winding diameter increases, and the product is a constant value. The inner lining layer yarn sheet prepared above is used for winding and forming. The yarn splitting tension is 5N~10N, the ply tension is 100~200N, the yarn output speed is 2m / s, and the winding thickness is 1mm.

[0111] S23. Support layer winding molding: The support layer yarn sheet prepared above is wound and molded, following the "equal torque" rule, with the yarn splitting tension being 5N~10N, the ply tension being 100~200N, the yarn output speed being 2m / s, and the winding thickness being 5mm.

[0112] S24. Overall bag sealing and autoclave curing: After winding, the product is cured in an autoclave at 180℃ and 0.3MPa. The viscosity of the resin under pressure is 40Pa·s. The product is sealed using a combination of "porous release film + absorbent felt + non-porous release film + air-conducting felt + vacuum bag". The amount of absorbent felt used is calculated using the following formula:

[0113]

[0114] Where: N—the number of layers of absorbent pad to be placed;

[0115] ρ f —Linear density of dry yarn, g / m;

[0116] ρ m —Linear density of the prepreg yarn, g / m;

[0117] W f —Design mass fraction of fiber in the product, %

[0118] d—Diameter of the core mold, mm;

[0119] D—Outer diameter of the product after winding, in mm;

[0120] M s —Theoretical adhesive absorption capacity of a single layer of absorbent felt (measured experimentally), g / cm³ 2 ;

[0121] ξ—Correction coefficient (1).

[0122] S25. Demolding and Machining: After the product has cured, demolding and machining are performed in the following order: outer diameter machining → demolding → cutting. The outer diameter of the product is machined by grinding, and water-based coolant is used. The single feed rate during machining is 1mm, and the single feed rate for the last 2mm margin is 0.5mm. The cutting is performed axially using a wire cutting device, and water-based coolant is used to obtain a self-lubricating bearing.

[0123] Example 4

[0124] The only difference from Example 1 is that the curing pressure in step S24 is 0.8 MPa.

[0125] Example 5

[0126] The only difference from Example 1 is that the curing pressure in step S24 is 1.2 MPa.

[0127] Example 6

[0128] The only difference from Example 4 is that the baking temperature in step S13 is 70°C.

[0129] Example 7

[0130] The only difference from Example 4 is that the baking temperature in step S13 is 90°C.

[0131] Example 8

[0132] The only difference from Example 4 is that the baking temperature in step S13 is 110°C.

[0133] Example 9

[0134] The only difference from Example 1 is that the powder supply pressure in step S13 is 0.1 MPa.

[0135] Example 10

[0136] The only difference from Example 1 is that the powder supply pressure in step S13 is 0.4 MPa.

[0137] Example 11

[0138] The only difference from Example 1 is that the traction speed in step S13 is 0.05 m / s.

[0139] Example 12

[0140] The only difference from Example 1 is that the traction speed in step S13 is 1.2 m / s.

[0141] Comparative Example 1

[0142] S1. The preparation of pre-impregnated yarn includes the following steps:

[0143] S11. Preparation of the inner lining fiber adhesive: 60 parts of Dow DER332 epoxy resin, 20 parts of NPEF170 epoxy resin, 20 parts of phenolic epoxy resin 638S, 5 parts of ethylene glycol diglycidyl ether, 5 parts of acetone, 5 parts of PTFE powder (50μm), 5 parts of graphite powder (10μm flakes), and 5 parts of MoS2 powder (10μm) are mixed evenly at 60℃. After stirring for 25 minutes, 70 parts of curing agent MHHPA, 2 parts of 2-ethyl-4-methylimidazole, and 3.5 parts of KH550 are added. Stirring is continued for another 20 minutes until evenly mixed. Vacuuming is performed for 30 minutes to remove bubbles, and the mixture is then transferred to an impregnation tank. Preparation of the support layer fiber adhesive: 60 parts of Dow DER332 epoxy resin, 20 parts of NPEF170 epoxy resin, and 638S of phenolic epoxy resin are mixed evenly. Mix 20 parts of ethylene glycol diglycidyl ether, 5 parts of acetone, and 5 parts of carbon black (N330) at 60℃ until homogeneous. After stirring for 25 minutes, add 70 parts of curing agent MHHPA, 2 parts of 2-ethyl-4-methylimidazole, and 3.5 parts of KH550. Continue stirring for 20 minutes until homogeneous. Then, vacuum for 30 minutes to remove bubbles and transfer to an impregnation tank.

[0144] S12. Yarn preparation: The inner lining layer consists of 70 parts polyester fiber yarn (1000D fineness) and 30 parts PTFE fiber yarn (400D fineness); the support layer is made of alkali-free glass fiber yarn (2000tex linear density).

[0145] S13. Hang the above fibers on the yarn rack. Prepare the inner lining layer and the support layer yarn separately using the same method. First, draw the fiber bundle tension to the impregnation system. After impregnation, control the glue content through the extrusion and scraping device. Calculate and control the fiber volume content to 50% (to remove solvent). Bake at 50°C for 12 minutes to remove certain solvents and low-volatile substances. When the resin reaches a certain degree of gelation, collect and store the yarn.

[0146] S2. The fabrication of a self-lubricating bearing includes the following steps:

[0147] S21. Core mold processing and installation: After grinding and cleaning the core mold, apply two coats of release agent and let it dry. Then install it onto the winding machine and adjust the position of the core mold.

[0148] S22. Inner lining layer winding: A four-dimensional winding machine is used for winding. The winding tension is selected according to the "equal torque" rule, that is, the winding tension decreases step by step as the winding diameter increases, and the product is a constant value. The inner lining layer yarn sheet prepared above is used for winding. The yarn splitting tension is 10N~15N, the ply tension is 60N~150N, the yarn output speed is 1.2m / s, and the winding thickness is 0.8mm.

[0149] S23. Support layer winding and forming: The support layer yarn sheet prepared above is wound and formed, following the "equal torque" rule, with the yarn splitting tension being 5N~10N, the ply tension being 60N~150N, the yarn output speed being 1.2m / s, and the winding thickness being 4mm.

[0150] S24. Overall bag sealing and autoclave curing: After winding, the product is cured in an autoclave at 200℃ and 0.2MPa. The viscosity of the resin under pressure is 25Pa·s. The product is sealed using a combination of "porous release film + absorbent felt + non-porous release film + air-conducting felt + vacuum bag". The amount of absorbent felt used is calculated using the following formula:

[0151]

[0152] Where: N—the number of layers of absorbent pad to be placed;

[0153] ρ f —Linear density of dry yarn, g / m;

[0154] ρ m —Linear density of the prepreg yarn, g / m;

[0155] W f —Design mass fraction of fiber in the product, %

[0156] d—Diameter of the core mold, mm;

[0157] D—Outer diameter of the product after winding, in mm;

[0158] M s —Theoretical adhesive absorption capacity of a single layer of absorbent felt (measured experimentally), g / cm³ 2 ;

[0159] ξ—Correction coefficient (0.6~1, derived empirically).

[0160] S25. Demolding and Machining: After the product has cured, demolding and machining are performed in the following order: outer diameter machining → demolding → cutting. The outer diameter of the product is machined by grinding, and water-based coolant is used. The single feed rate during machining is 1mm, and the single feed rate for the last 2mm margin is 0.5mm. The cutting is performed axially using a wire cutting device, and water-based coolant is used to obtain a self-lubricating bearing.

[0161] Comparative Example 2

[0162] The only difference from Example 1 is that the product after winding in step S24 is cured at 180°C using a forced-air drying oven.

[0163] Comparative Example 3

[0164] The only difference from Example 1 is that the curing pressure in step S24 is 0.1 MPa.

[0165] Comparative Example 4

[0166] The only difference from Example 1 is that the curing pressure in step S24 is 1.5 MPa.

[0167] The self-lubricating bearings obtained in Examples 1-12 and Comparative Examples 1-4 were tested for fiber volume content (GB / T 2577-2005), void content (JC / T 287-2010), and compressive strength (GB / T 1448-2005). The test results are recorded in Table 1.

[0168] Table 1. Cavity content and compressive strength of self-lubricating bearings

[0169]

[0170] As can be seen from Table 1, the self-lubricating bearing provided by the present invention has a void content of less than 2.3% and a compressive strength of more than 350 MPa, exhibiting both low void content and high strength.

[0171] Compared with Comparative Examples 2-4, the self-lubricating bearing obtained in Example 1 had a lower void content and higher compressive strength than Comparative Examples 2-4. This indicates that applying pressure during the curing process and controlling the pressure during the curing process to be 0.3MPa~1.2MPa reduced the void content of the self-lubricating bearing and improved its strength.

[0172] Compared with Comparative Example 1, the self-lubricating bearing obtained in Example 1 had a lower void content and a higher compressive strength, indicating that the electrostatic powder spraying method further reduced the void content of the self-lubricating bearing and further improved its strength.

[0173] The self-lubricating bearings obtained in Examples 6 and 7 had lower void content and higher compressive strength than those in Examples 4 and 8, indicating that baking the adhesive in the yarn at 70°C to 90°C for 5 to 20 minutes further reduced the void content of the self-lubricating bearings and further improved their strength.

[0174] The self-lubricating bearing obtained in Example 1 had a lower void content and higher compressive strength than that in Examples 9-10, indicating that the powder supply pressure of 0.15MPa-0.3MPa further reduced the void content of the self-lubricating bearing and further improved its strength.

[0175] The self-lubricating bearing obtained in Example 1 has a lower void content and higher compressive strength than that in Examples 11-12, indicating that the traction speed of 0.1-1 m / s further reduces the void content of the self-lubricating bearing and further improves its strength.

[0176] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing a self-lubricating bearing, characterized in that, Includes the following steps: The pre-impregnated yarn is cured to obtain a self-lubricating bearing, wherein the curing pressure is 0.8MPa~1.2MPa; The method for preparing the prepreg yarn includes the following steps: depositing filler on the surface of the impregnated fiber bundle, and baking at 70℃~90℃ for 5min~20min to obtain the prepreg yarn; The impregnation solution comprises the following raw materials in parts by weight: 60-120 parts epoxy resin, 40-105 parts curing agent, 1-5 parts accelerator, and 5-30 parts additives. The auxiliary agent includes 2-10 parts of coupling agent, 1-10 parts of diluent, and 2-10 parts of solvent; The deposited filler is specifically deposited using an electrostatic powder spraying process during the fiber bundle traction process after impregnation. The powder supply pressure during electrostatic powder spraying is 0.15MPa~0.3MPa; the traction speed is 0.1~1m / s. The prepreg yarn comprises, from the inside out, an inner lining prepreg yarn and a support layer prepreg yarn. The raw materials of the inner lining prepreg yarn include polyester fiber and PTFE fiber, and the raw materials of the support layer prepreg yarn include one or more of alkali-free glass fiber, basalt fiber, carbon fiber, and high-silica glass fiber cloth.

2. The method for producing a self-lubricating bearing according to claim 1, characterized in that, The curing temperature is 180℃~200℃.

3. The method for producing a self-lubricating bearing according to claim 1, characterized in that, The electrostatic voltage during electrostatic powder spraying is 30kV~70kV, and the spraying distance is 200mm~500mm.

4. The method for producing a self-lubricating bearing according to claim 1, characterized in that, The preparation method of the adhesive includes the following steps: after mixing epoxy resin, diluent and solvent, add the remaining components and mix evenly to obtain the adhesive.

5. The method for producing a self-lubricating bearing according to claim 4, characterized in that, The epoxy resin comprises 60-100 parts of bisphenol A type epoxy resin, 0-60 parts of bisphenol F type epoxy resin, and 0-20 parts of phenolic epoxy resin. And / or, The filler includes one or more of PTFE powder, graphite powder, BN powder, MoS2, and carbon black; And / or, During the curing process, pressure is applied, and the viscosity of the resin during the pressure application is 10 Pa•s to 40 Pa•s. And / or, Before the deposition of the filler, the process also includes extrusion and scraping of the glue. The glue content is controlled by extrusion and scraping to ensure that the fiber volume content in the prepreg yarn is 45% to 60%. And / or, The curing agent is an acid anhydride-based latent curing agent; And / or, The accelerator includes one or more of tertiary amine salt complexes, Lewis acid complexes, and imidazole accelerators; And / or, The diluent includes one or more of ethylene glycol diglycidyl ether, phenyl glycidyl ether, and diglycidyl ether. And / or, The solvent includes one or both of acetone and ethanol.

6. The method for producing a self-lubricating bearing according to claim 1, characterized in that, The mass ratio of the polyester fiber to the PTFE fiber is 30~70:20~50; And / or, The fiber fineness of the prepreg yarn in the inner lining layer is 400D~1000D, and the fiber fineness of the prepreg yarn in the support layer is 1500tex~3000tex; And / or, The raw materials for the prepreg yarn of the inner lining layer also include 0-30 parts of aramid fiber and 0-30 parts of ultra-high molecular weight polyethylene fiber.

Images