High temperature wear resistant cylindrical roller bearing

Abstract

The application relates to a high-temperature wear-resistant cylindrical roller bearing, which solves the problem that the hardness and wear resistance of the existing cylindrical roller bearing are poor under high-temperature working conditions, the service life is short, and the reliability cannot be guaranteed, and belongs to the technical field of bearings. The wear-resistant cylindrical roller bearing comprises a bearing outer ring, a bearing inner ring, a roller and a retainer, the axial two ends of the bearing outer ring are respectively provided with annular retaining flanges extending radially inward, a plurality of axial through holes are arranged on the annular retaining flanges, the plurality of axial through holes are uniformly distributed in the circumferential direction on the annular retaining flanges, the axial lines of the axial through holes are parallel to the axis of the bearing, the axial through holes are filled with first solid lubricant, and the bearing outer ring, the bearing inner ring and the roller are all made of high-entropy alloy material. The application can normally work under high-temperature working conditions of 500-800 DEG C, prolongs the high-temperature service life of the bearing, and improves the reliability of a space vehicle.

Description

Technical Field

[0001] This invention relates to a high-temperature wear-resistant cylindrical roller bearing, belonging to the field of bearing technology. Background Technology

[0002] With the development of aerospace technology, the requirements for the temperature resistance of bearings in spacecraft are constantly increasing, with the extreme operating temperature rising from the conventional 250℃ to 500-800℃. Under these high-temperature, heavy-load conditions, the friction and wear problems of cylindrical roller bearings are very serious, greatly limiting the bearing's lifespan and load-bearing capacity. Traditional bearing materials are mainly divided into the following categories:

[0003] Low alloy steel, with GCr 15 As a representative. GCr 15 It requires long-term high-temperature dimensional stabilization treatment and has a long-term operating temperature below 200℃. It is mainly used in civilian bearings and ordinary bearings with low operating temperatures.

[0004] High-alloy bearing steels, represented by the Cr4Mo4V (M50) series, are high-performance bearing steels primarily used in critical fields such as aerospace. M50 bearing steel exhibits good high-temperature dimensional stability, high-temperature hardness, and high-temperature contact fatigue performance, with a proven long-term operating temperature up to 350℃. Above this temperature, its wear resistance significantly decreases, and its high-temperature fatigue life is insufficient.

[0005] Besides the limitations of the materials themselves, the lubrication design of traditional bearings at extreme high temperatures also faces severe challenges. When the operating temperature exceeds the limit, continuous and effective lubrication is required throughout the entire lifespan of the bearing to prevent increased friction between the rollers and raceways, and between the rollers and flanges, which could lead to increased wear and bearing failure.

[0006] In summary, when faced with extreme high-temperature conditions of 500–800℃, traditional bearing materials, due to insufficient hardness and wear resistance, and the lack of an effective lubrication mechanism, can hardly meet the requirements for service life and reliability under high-temperature conditions. Summary of the Invention

[0007] This invention addresses the problem that existing cylindrical roller bearings have poor hardness and wear resistance under ultra-high temperature conditions, resulting in short service life and unreliable reliability. Therefore, it proposes a high-temperature wear-resistant cylindrical roller bearing.

[0008] The technical solution adopted by the present invention to solve the above problems is as follows:

[0009] This invention proposes a high-temperature wear-resistant cylindrical roller bearing, comprising an outer bearing ring, an inner bearing ring, rollers, and retaining rings. The outer bearing ring has radially inwardly extending annular retaining edges at both axial ends. Multiple axial through holes are provided on the annular retaining edges, evenly distributed circumferentially on the annular retaining edges. The axes of the axial through holes are parallel to the bearing axis. A first solid lubricant is filled within the axial through holes. The outer bearing ring, the inner bearing ring, and the rollers are all made of high-entropy alloy material.

[0010] Furthermore, the inner ring of the bearing has multiple radial through holes on its raceway, which are evenly distributed along the circumference. The axis of each radial through hole is perpendicular to the axis of the bearing, and the radial through holes are filled with a third solid lubricant.

[0011] Furthermore, the radial through holes are divided into several radial through hole groups, each radial through hole group includes multiple radial through holes, the multiple radial through holes of each radial through hole group are evenly distributed along the same circumferential direction on the raceway of the inner ring of the bearing, and the several radial through hole groups are evenly distributed along the axial direction on the raceway of the inner ring of the bearing.

[0012] Furthermore, both the first solid lubricant filling the axial through hole and the third solid lubricant filling the radial through hole are graphite.

[0013] Furthermore, the outer ring of the bearing has an annular groove on its raceway, the annular groove being located at the axial center of the raceway of the outer ring of the bearing, and the annular groove being filled with a second solid lubricant.

[0014] Furthermore, the second solid lubricant filled in the annular groove is silver.

[0015] Furthermore, the chemical formula of the high-entropy alloy is Al. 0.5 CoCrFeW 0.5 The atomic molar ratio of Al, Co, Cr, Fe, W and Ni in the high-entropy alloy is 0.5:1:1:1:0.5:1.

[0016] Furthermore, the raceway surfaces of the outer ring and the inner ring of the bearing are respectively provided with an ion implantation modification layer, a hard coating layer, and a lubricating coating layer from the inside out.

[0017] Furthermore, the ion implantation modification layer is a modification layer formed by C and N ion implantation on the raceway surface of the outer ring of the bearing and the raceway surface of the inner ring of the bearing; the hard coating is an AlTiN coating; and the lubricating coating is an Ag coating.

[0018] Furthermore, the thickness of the hard coating is 2 μm, and the thickness of the lubricating coating is 5 μm.

[0019] The beneficial effects of this invention are:

[0020] 1. Because the bearing outer ring, bearing inner ring and rollers of the present invention are all made of high-entropy alloy material with high temperature resistance, combined with the setting of ion implantation modification layer, hard coating and lubricating coating on the raceway surface of the bearing outer ring and bearing inner ring, it can work normally under high temperature conditions of 500-800℃, extend the high temperature service life of the bearing and improve the reliability of spacecraft.

[0021] 2. This invention provides solid lubrication to the bearing during operation by filling the axial through hole of the bearing outer ring and the radial through hole of the bearing inner ring with graphite, thereby reducing the bearing's friction coefficient, reducing material loss and energy consumption, and improving the bearing's service life and reliability under ultra-high temperature conditions. At the same time, the graphite in this structure is easy to replenish under non-operating conditions.

[0022] 3. This invention embeds silver in an annular groove at the center of the outer ring raceway of the bearing. Its layered crystal structure makes it easy to undergo shear slip, which can form a continuous and stable lubricating film on the friction surface, effectively reducing the coefficient of friction. At the same time, silver has good thermal and electrical conductivity, which can dissipate the heat generated by friction in time and avoid lubrication failure caused by higher local temperature. In addition, silver has high chemical stability and can maintain excellent lubrication performance even in high temperature environments. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of the overall structure of the cylindrical roller bearing of the present invention;

[0024] Figure 2 This is a cross-sectional view of the outer ring of the cylindrical roller bearing of the present invention;

[0025] Figure 3 yes Figure 2 Side view of the bearing outer ring according to the embodiment;

[0026] Figure 4 yes Figure 2 Enlarged structural diagram of section A in the middle;

[0027] Figure 5 This is a cross-sectional view of the inner ring of the cylindrical roller bearing of the present invention.

[0028] Figure 6 yes Figure 5 A magnified structural diagram of section B.

[0029] In the figure: 1-bearing outer ring; 101-ion implantation modified layer; 102-hard coating; 103-lubricating coating; 2-bearing inner ring; 3-roller; 4-retaining ring; 5-first solid lubricant; 6-second solid lubricant; 7-third solid lubricant. Detailed Implementation

[0030] This embodiment proposes a high-temperature wear-resistant cylindrical roller bearing, such as... Figure 1 As shown, the bearing includes an outer ring 1, an inner ring 2, rollers 3, and a retaining ring 4. A raceway is formed between the outer ring 1 and the inner ring 2. The rollers 3 are evenly distributed circumferentially within the raceway. The retaining ring 4 is fixed to both axial sides of the inner ring 2 to prevent the rollers 3 from axially falling off. Figure 2 , Figure 3 As shown, the outer ring 1 of the bearing has radially inwardly extending annular flanges at both axial ends for positioning the rollers 3. The purpose of the annular flanges for positioning the rollers 3 is to ensure that the position of the axial through holes corresponds to that of the rollers 3, so that the solid lubricant inside can lubricate the rollers. Each annular flange has multiple axial through holes evenly distributed along its circumference, which axially penetrate the annular flange, and the number of these through holes is usually 6-8. The axis of the axial through holes is parallel to the axis of the bearing, and the axial through holes are filled with a first solid lubricant 5. Figure 5 As shown, the raceway of the bearing inner ring 2 is provided with multiple radial through holes evenly distributed along the circumference (of the bearing inner ring). These radial through holes radially penetrate the bearing inner ring 2, and their axes are perpendicular to the bearing axis. The radial through holes can be divided into several groups, each group comprising multiple radial through holes. These radial through holes in each group are evenly distributed along the same circumferential direction on the raceway of the bearing inner ring 2. The groups of radial through holes are also evenly distributed axially on the raceway of the bearing inner ring 2. Each group can contain 6-8 radial through holes, and the radial through holes in adjacent groups correspond one-to-one axially to each other on the bearing inner ring. The radial through-hole is filled with a third solid lubricant 7. Both the first solid lubricant 5 and the third solid lubricant 7 are graphite. Graphite is a solid lubricant with a unique layered structure and excellent high temperature and pressure resistance. The graphite in the axial and radial through-holes can provide solid lubrication for the bearing when the bearing is working (mainly referring to the lubrication between the roller 3 and the inner ring 2 of the bearing and the lubrication between the roller 3 and the annular flange), reducing the friction coefficient of the bearing, reducing material loss and energy consumption, and improving the service life and reliability of the bearing under ultra-high temperature conditions. At the same time, the graphite in this structure is easy to replenish under non-working conditions.

[0031] Preferably, the raceway of the outer ring 1 of the bearing is provided with an annular groove, which is located at the axial center of the raceway of the outer ring 1. A second solid lubricant 6, which is silver, is embedded (or filled) in the annular groove. Silver has unique lubrication properties. Its layered crystal structure makes it easy to undergo shear slip, which can form a continuous and stable lubricating film on the friction surface, effectively reducing the coefficient of friction. At the same time, silver has good thermal and electrical conductivity, which can dissipate the heat generated by friction in time and avoid lubrication failure caused by higher local temperatures. In addition, silver has high chemical stability and can maintain excellent lubrication performance even at high temperatures.

[0032] Traditional bearing materials are insufficient to meet the requirements of extreme high-temperature conditions of 500–800℃. Therefore, high-entropy alloys, as a novel bearing material, can maintain high strength even at 800℃, and their wear resistance can be 2-3 times that of traditional bearing materials. Their thermal expansion coefficient can be controlled through composition design. In this embodiment, the outer ring 1, inner ring 2, and roller 3 of the bearing are all made of high-entropy alloy material Al. 0.5 CoCrFeW 0.5 Made from Ni. Al 0.5 CoCrFeW 0.5 Ni is a multi-principal-element high-entropy alloy, comprising Al, Co, Cr, Fe, W, and Ni metallic elements, with an atomic molar ratio of 0.5:1:1:1:0.5:1. The preparation method of the high-entropy alloy is as follows:

[0033] Step 1, Prepare materials:

[0034] Al, Co, Cr, Fe, W and Ni metal raw materials were selected and prepared in an atomic molar ratio of 0.5:1:1:1:0.5:1;

[0035] Step 2, Feeding:

[0036] The prepared raw materials are put into the vacuum suspension melting furnace, and the raw materials are added in order of increasing melting point;

[0037] Step 3: Heating and Melting:

[0038] Melting is carried out with a power of 600KW to heat the casting material to a completely melted temperature of 2200-2500℃. It takes 25-35 minutes to heat the casting material from 0℃ to 2500℃.

[0039] Step 4, Refining:

[0040] After melting and cleaning, refining is carried out at a power of 600KW, a refining time of 8-12 minutes, and a temperature of 2200-2500℃.

[0041] Step 5, Cooling:

[0042] After refining, the temperature is lowered and the material is poured. Then it is cooled in the furnace to the tapping temperature, and the cooling time is 35-45 minutes.

[0043] Step 6: Repeat steps 3 to 5 at least five times with the ingot obtained in step 5.

[0044] High-entropy alloy Al 0.5 CoCrFeW 0.5 Ni exhibits excellent strength, high-temperature stability, high-temperature wear resistance, and oxidation resistance, and performs well in high-temperature environments.

[0045] To further improve the bearing's performance under high-temperature conditions, the following treatments are performed sequentially from the inside out on both the raceway surface of the outer ring 1 and the raceway surface of the inner ring 2:

[0046] like Figure 4 and Figure 6 As shown, C and N ion implantation modification is performed on the raceway surface of the outer ring 1 and the raceway surface of the inner ring 2 of the bearing (the modification can be carried out using existing ion implantation modification methods) to form an ion implantation modification layer 101, which improves its surface hardness, up to 1200H, and improves the wear resistance, corrosion resistance and fatigue performance of the bearing surface, thereby improving the fatigue life of the bearing. At the same time, it can also inhibit the interdiffusion of elements between the coating and the substrate, enhance the coating adhesion, and improve the effect of subsequent coating treatment.

[0047] A 2 μm thick AlTiN coating is deposited on the ion-implanted modified layer 101 using a physical method to form a hard coating 102, further improving the hardness and wear resistance of the raceway surface. This coating maintains high hardness even at 800°C, and a dense oxide film is formed at high temperatures, preventing oxygen diffusion inward and inhibiting substrate softening, thereby improving the bearing's high-temperature oxidation resistance and stability. The coating also has a low coefficient of friction, reducing frictional resistance during bearing operation, lowering energy loss, and improving bearing efficiency. It also helps reduce heat generated by friction, preventing bearing failure due to operating temperatures exceeding 800°C.

[0048] A 5 μm thick Ag coating is deposited on the hard coating 102 using a physical method to form a lubricating coating 103. The Ag coating has good self-lubricating properties and excellent thermal conductivity, which can quickly conduct away the heat generated by the bearing during operation, improving the bearing's thermal stability. Under high-temperature environments, the Ag coating can form a dense oxide film, reducing oxidation loss, and also has a certain resistance to various corrosive media, preventing the bearing from being chemically corroded.

[0049] The bearing in this embodiment can be a single-row cylindrical roller bearing or a double-row cylindrical roller bearing.

[0050] Example 1

[0051] Single-row cylindrical roller bearings are selected. The bearing inner ring dimensions are: inner diameter 15mm and width 11mm; the bearing outer ring dimensions are: outer diameter 35mm and width 11mm.

[0052] Lubrication method: axial and radial through holes are filled with graphite solid lubricant; silver lubricant is embedded in the annular groove;

[0053] Materials and Coatings: The bearing inner ring, outer ring, and rollers are all made of Al. 0.5 CoCrFeW 0.5 Made of Ni high-entropy alloy, the raceway surfaces of the inner ring and outer ring of the bearing are sequentially provided with an ion implantation modification layer, an AlTiN hard coating (2μm), and an Ag lubricating coating (5μm).

[0054] The friction and wear performance of the cylindrical roller bearing was tested at room temperature, 500℃, and 800℃ under a radial load of 4500N and a test time of 2 hours. The test results are shown in Table 1. The test results show that the cylindrical roller bearing can still meet the usage requirements in terms of friction coefficient and wear after stable operation for 2 hours under the above test conditions.

[0055] Table 1. Test results of friction and wear performance in Example 1

[0056]

[0057] Example 2

[0058] Single-row cylindrical roller bearings are selected. The bearing inner ring dimensions are: inner diameter 20mm and width 14mm; the bearing outer ring dimensions are: outer diameter 47mm and width 14mm.

[0059] Lubrication method: Same as in Example 1;

[0060] Materials and coatings: Same as in Example 1.

[0061] Under a radial load of 7000 N and a test duration of 2 hours, the friction and wear performance of this cylindrical roller bearing was tested at room temperature, 500℃, and 800℃. The test results are shown in Table 2. The test results show that the cylindrical roller bearing can still meet the usage requirements in terms of friction coefficient and wear after stable operation for 2 hours under the above test conditions.

[0062] Table 2. Test results of friction and wear performance in Example 2

[0063]

[0064] Example 3

[0065] Double-row cylindrical roller bearings are selected. The bearing inner ring dimensions are: inner diameter 20mm and width 25mm; the bearing outer ring dimensions are: outer diameter 52mm and width 24mm.

[0066] Lubrication method: Same as in Example 1;

[0067] Materials and coatings: Same as in Example 1.

[0068] The friction and wear performance of the cylindrical roller bearing was tested at room temperature, 500℃, and 800℃ under a radial load of 8000N and a test time of 2 hours. The test results are shown in Table 3. The test results show that the cylindrical roller bearing can still meet the usage requirements in terms of friction coefficient and wear after stable operation for 2 hours under the above test conditions.

[0069] Table 3. Test results of friction and wear performance in Example 3

[0070]

[0071] Comparative Example 1:

[0072] The cylindrical roller bearing in this comparative example has the same structural dimensions and lubrication method as that in Example 1, but the difference is that the inner ring, outer ring and rollers of the bearing are all made of GH4169 high-temperature alloy, and the raceway surface is not surface treated.

[0073] Using the same loading conditions as in Example 1, the friction and wear performance of the cylindrical roller bearing was tested at room temperature, 500℃, and 800℃ under a radial load of 4500N and a test time of 2 hours. The test results are shown in Table 4.

[0074] Table 4. Test results of friction and wear performance of Comparative Example 1

[0075]

[0076] By comparing Table 1 of Example 1 and Table 4 of Comparative Example 1, it can be seen that the coefficient of friction of the cylindrical roller bearing in Comparative Example 1 is significantly higher than that in Example 1 at room temperature, and the wear is also larger, reaching 0.068 mm. During testing above 500°C, due to the degradation of the high-temperature alloy material at high temperatures and the fact that the rollers and inner and outer rings have the same composition, welding occurred during the high-temperature friction process, leading to bearing failure.

[0077] Comparative Example 2:

[0078] The cylindrical roller bearing in this comparative example has the same structural dimensions, lubrication method, and materials as in Example 1, but the raceway surface is not surface-treated.

[0079] Using the same loading conditions as in Example 1, the friction and wear performance of the cylindrical roller bearing was tested at room temperature, 500℃, and 800℃ under a radial load of 4500N and a test time of 2 hours. The test results are shown in Table 5.

[0080] Table 5. Test results of friction and wear performance of Comparative Example 2

[0081]

[0082] A comparison of Table 1 in Example 1 and Table 5 in Comparative Example 2 reveals that, under various temperature conditions, the friction coefficient of the cylindrical roller bearing in Comparative Example 2 is significantly higher than that in Example 1, and the wear is also greater, especially at 500℃ and 800℃, where the wear reaches 0.147mm and 0.191mm respectively, indicating that the bearing cannot meet the usage requirements under these test conditions. Therefore, the surface treatment method provided by this invention can effectively improve the hardness of the bearing raceway surface, reduce friction, and decrease wear, playing a crucial role in its safe use at high temperatures.

[0083] The bearings described in the above embodiments, by employing the Al 0.5 CoCrFeW 0.5 The Ni high-entropy alloy material, composite surface coating, and solid lubrication structure all exhibit excellent performance under corresponding high-temperature and high-load conditions, verifying the beneficial effects of this invention in extending high-temperature service life and improving reliability.

[0084] Unless otherwise specified or further limited to one preferred or optional technical means being another, the preferred and optional technical means disclosed in this invention can be arbitrarily combined to form several different technical solutions.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A high-temperature wear-resistant cylindrical roller bearing, comprising a bearing outer ring (1), a bearing inner ring (2), rollers (3) and a retainer ring (4), a raceway is formed between the bearing outer ring (1) and the bearing inner ring (2), the rollers (3) are uniformly distributed in the raceway in the circumferential direction, the retainer ring (4) is fixed on the axial both sides of the bearing inner ring (2), the axial both ends of the bearing outer ring (1) are respectively provided with annular flanges extending radially inward, a plurality of axial through holes are provided on the annular flanges, the plurality of axial through holes are uniformly distributed on the annular flanges in the circumferential direction, the axis of the axial through hole is parallel to the axis of the bearing, the axial through hole is filled with a first solid lubricant (5), the bearing outer ring (1), the bearing inner ring (2) and the roller (3) are all made of high-entropy alloy material, the raceway surface of the bearing outer ring (1) and the raceway surface of the bearing inner ring (2) are sequentially provided with an ion implantation modified layer (101), a hard coating (102) and a lubricating coating (103) from inside to outside; characterized in that: The ion implantation modification layer (101) is a modification layer formed by implanting C and N ions on the raceway surface of the bearing outer ring (1) and the raceway surface of the bearing inner ring (2); the hard coating (102) is an AlTiN coating; and the lubricating coating (103) is an Ag coating.

2. A high-temperature, wear-resistant cylindrical roller bearing according to claim 1, characterized in that: The raceway of the bearing inner ring (2) is provided with a plurality of radial through holes, the plurality of radial through holes are uniformly distributed along a circumferential direction on the raceway of the bearing inner ring (2), the axis of the radial through hole is perpendicular to the axis of the bearing, and the radial through hole is filled with a third solid lubricant (7).

3. A high-temperature, wear-resistant cylindrical roller bearing according to claim 2, characterized in that: The radial through holes are divided into a plurality of radial through hole groups, each radial through hole group comprises a plurality of radial through holes, the plurality of radial through holes of each radial through hole group are uniformly distributed along the same circumferential direction on the raceway of the bearing inner ring (2), and the plurality of radial through hole groups are uniformly distributed along an axial direction on the raceway of the bearing inner ring (2).

4. A high-temperature, wear-resistant cylindrical roller bearing according to claim 2, characterized in that: The first solid lubricant (5) filled in the axial through hole and the third solid lubricant (7) filled in the radial through hole are both graphite.

5. A high-temperature, wear-resistant cylindrical roller bearing according to claim 1, wherein: The raceway of the bearing outer ring (1) is provided with an annular groove, the annular groove is located at the axial center position of the raceway of the bearing outer ring (1), and the annular groove is filled with a second solid lubricant (6).

6. A high-temperature, wear-resistant cylindrical roller bearing according to claim 5, characterized in that: The second solid lubricant (6) filled in the annular groove is silver.

7. A high-temperature, wear-resistant cylindrical roller bearing according to claim 1, wherein: The high-entropy alloy has a chemical formula of Al 0.5 CoCrFeW 0.5 Ni, and an atomic mole ratio of Al, Co, Cr, Fe, W and Ni in the high-entropy alloy is 0.5:1:1:1:0.5:

1.

8. A high-temperature, wear-resistant cylindrical roller bearing according to claim 1, wherein: The thickness of the hard coating (102) is 2 microns, and the thickness of the lubricating coating (103) is 5 microns.

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