Rolling bearing of composite material

Abstract

The application provides a composite rolling bearing and relates to the technical field of bearings. The rolling bearing comprises an inner ring, a rolling assembly and an outer ring which are concentrically arranged, the rolling assembly comprises a retainer and a plurality of rolling elements arranged in the retainer, the plurality of rolling elements are arranged between the inner ring and the outer ring and roll, the inner ring comprises a first contact layer, an inner surface layer is arranged on the inner side of the first contact layer, the outer ring comprises a second contact layer, an outer surface layer is arranged on the outer side of the second contact layer, the elastic modulus of the first contact layer is greater than that of the inner surface layer, and the elastic modulus of the second contact layer is greater than that of the outer surface layer. The application can improve the mechanical properties of the bearing, the radial deformation of the sleeve ring is greater when the rolling elements are in contact, the contact area can be effectively increased, the contact stress can be reduced, therefore, compared with the same type of rolling bearing, the composite rolling bearing is lighter, can bear greater load and has a longer service life.

Description

Technical Field

[0001] This invention relates to the field of bearing technology, and more specifically, to a rolling bearing made of composite materials. Background Technology

[0002] With the rapid development of industries such as aerospace, the performance requirements for rolling bearings, including lightweighting, high temperature resistance, and high strength, are becoming increasingly stringent. Rolling bearings are an important component in modern mechanical equipment. Their main function is to support rotating mechanical parts, reduce the coefficient of friction during their movement, and ensure their rotational accuracy.

[0003] Traditional rolling bearings, widely used in the aerospace industry, are made of a single material (such as bearing steel or ceramics) for their rolling elements, inner ring, and outer ring. However, traditional single-material rolling bearings often fail to perform well under harsh operating conditions, especially under heavy loads. The large effective contact area between the rolling elements and the inner and outer rings, coupled with high contact stress between the rolling elements and the raceways, easily damages the lubricating oil film, leading to bearing failure due to wear. This results in a short overall lifespan for rolling bearings. Furthermore, they are complex and heavy, exhibit significant dimensional inaccuracies during high and low temperature cycling, and have poor environmental adaptability.

[0004] In summary, we propose a composite material rolling bearing to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a composite material rolling bearing that improves the mechanical properties of the bearing. When in contact with the rolling elements, the radial deformation of the bearing rings is greater, which can effectively increase the contact area and reduce the contact stress. Therefore, compared with the same type of rolling bearing, the composite material rolling bearing is lighter, can withstand greater loads, and has a longer service life.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A composite material rolling bearing includes a concentrically arranged inner ring, a rolling assembly, and an outer ring. The rolling assembly includes a cage and a plurality of rolling elements disposed within the cage. The plurality of rolling elements are rotatably disposed between the inner ring and the outer ring. The inner ring includes a first contact layer and an inner surface layer disposed inside the first contact layer. The outer ring includes a second contact layer and an outer surface layer disposed outside the second contact layer. The elastic modulus of the first contact layer is greater than that of the inner surface layer, and the elastic modulus of the second contact layer is greater than that of the outer surface layer.

[0008] This rolling bearing not only meets the requirements of sufficient strength and hardness of the rolling elements, but also has higher wear resistance, corrosion resistance and elastic limit, which is conducive to further enhancing the contact fatigue strength and dimensional stability of the raceway. It can also combine the advantages of two different materials. Under different working environment requirements, it can integrate the advantages of each component and make up for the deficiencies, and has comprehensive performance that is difficult to achieve with a single metal or alloy material.

[0009] Furthermore, in this invention, the aforementioned cage is an injection-molded structure.

[0010] This design method makes processing more convenient.

[0011] Furthermore, in this invention, the first contact layer is made of bearing steel, and the inner surface layer is made of aluminum alloy.

[0012] This design approach satisfies both the strength and hardness requirements of the bearing during operation, while also reducing the overall weight of the bearing's inner ring.

[0013] Furthermore, in this invention, the material of the second contact layer is bearing steel, and the material of the outer surface layer is titanium alloy.

[0014] This design uses bearing steel for the second contact layer and titanium alloy for the outer layer. Its corrosion resistance is far superior to that of stainless steel when working in humid atmospheres and seawater.

[0015] Furthermore, in this invention, the material of the rolling element is a ceramic matrix composite material.

[0016] This design gives the rolling element excellent properties such as high temperature resistance, high strength and rigidity, relatively light weight, and corrosion resistance.

[0017] Furthermore, in this invention, when the inner ring rotates and the outer ring is fixed, both the first contact layer and the inner surface layer are annular rings of uniform thickness. The surface of the second contact layer that contacts the outer surface layer protrudes outward to form a first arc-shaped member, and the outer surface layer is provided with a first inner groove relative to the first arc-shaped member.

[0018] In this design, when the inner ring rotates and the outer ring is fixed, personnel can make corresponding adjustments according to the load distribution pattern, so that the bearing can withstand a greater load strength.

[0019] Furthermore, in this invention, when the inner ring is fixed and the outer ring is rotated, both the second contact layer and the outer surface layer are annular rings of uniform thickness. The surface of the first contact layer that contacts the inner surface layer is concave to form a second concave arc groove, and the outer surface layer convexes outward relative to the second concave arc groove to form a second arc-shaped component.

[0020] In this design, when the inner ring is fixed and the outer ring rotates, personnel can make corresponding adjustments according to the load distribution pattern, so that the bearing can withstand a greater load strength.

[0021] The present invention has at least the following advantages or beneficial effects:

[0022] The inner ring of the rolling bearing is formed by extrusion bonding of a first contact layer and an inner surface layer, and the outer ring is formed by extrusion bonding of a second contact layer and an outer surface layer. The elastic modulus of the first contact layer is greater than that of the inner surface layer, and the elastic modulus of the second contact layer is greater than that of the outer surface layer. This reduces the weight of the bearing and increases the load it can withstand. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a composite material rolling bearing according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 Schematic diagram of the middle cage;

[0026] Figure 3 This is a cross-sectional view of the inner ring of a composite material rolling bearing when the inner ring rotates and the outer ring is fixed, according to an embodiment of the present invention.

[0027] Figure 4 This is a cross-sectional view of the outer ring in a composite material rolling bearing according to an embodiment of the present invention, where the inner ring rotates and the outer ring is fixed.

[0028] Figure 5 This is a cross-sectional view of the inner ring when the outer ring is fixed in a rolling bearing made of composite material according to an embodiment of the present invention.

[0029] Figure 6 This is a cross-sectional view of the outer ring when the inner ring is fixed and the outer ring rotates in a composite material rolling bearing according to an embodiment of the present invention.

[0030] Figure 7 This invention describes the bearing load distribution law under radial load in a composite material rolling bearing according to an embodiment of the present invention.

[0031] Figure 8 This is a solution process for determining the bearing load distribution in a composite rolling bearing according to an embodiment of the present invention.

[0032] Icons: 1-rolling element, 2-cage, 3-inner ring, 4-outer ring, 5-first contact layer, 6-inner surface layer, 7-second contact layer, 8-outer surface layer, 9-first arc-shaped component, 10-first inner groove, 11-second arc-shaped component, 12-second inner groove. Detailed Implementation

[0033] Example

[0034] Please refer to Figures 1-8 The composite material rolling bearing includes a concentrically arranged inner ring 3, a rolling assembly, and an outer ring 4. The rolling assembly includes a cage 2 and a plurality of rolling elements 1 disposed within the cage 2. The plurality of rolling elements 1 are rolled between the inner ring 3 and the outer ring 4. The inner ring 3 includes a first contact layer 5, and an inner surface layer 6 is disposed on the inner side of the first contact layer 5. The outer ring 4 includes a second contact layer 7, and an outer surface layer 8 is disposed on the outer side of the second contact layer 7. The elastic modulus of the first contact layer 5 is greater than that of the inner surface layer 6, and the elastic modulus of the second contact layer 7 is greater than that of the outer surface layer 8.

[0035] The inner ring 3 of the composite material is formed by extrusion bonding between the first contact layer 5 and the inner surface layer 6, and the outer ring of the composite material is formed by extrusion bonding between the second contact layer 7 and the outer surface layer 8. The rolling assembly is located between the first contact layer 5 and the second contact layer 7. The cage 2 has multiple limiting holes, the number of which is equal to and corresponds one-to-one with the number of rolling elements 1. The multiple limiting holes are evenly distributed on the cage 2. When the rolling bearing starts working, the multiple rolling elements 1 roll, turning the friction between the outer ring 4 and the inner ring 3 into rolling friction. The elastic modulus of the first contact layer 5 and the second contact layer 7 are greater than the elastic modulus of the inner surface layer 6 and the outer surface layer 8, respectively, so that the rolling elements 1... The inner ring 3 and outer ring 4 of the rolling bearing are made of composite materials. Compared with single-material rings, the inner ring 3 and outer ring 4 of the composite material contain a certain amount of low elastic modulus relative to their own requirements. This makes the inner ring 3 and outer ring 4 lighter overall than the inner ring 3 and outer ring 4 of current bearings (because the low elastic modulus material corresponds to a lower density value). The equivalent elastic modulus is lower than that of the ring contact layer material. Under the same load, the inner ring 3 and outer ring 4 of this composite material bearing have better mechanical properties than the inner ring 3 and outer ring 4 of single material. When in contact with the rolling element 1, the radial deformation of the inner ring 3 and outer ring 4 is greater, which can effectively increase the contact area, reduce the contact stress, and increase the load value that can be withstood. This rolling bearing not only meets the requirements of sufficient strength and hardness of the rolling element 1, but also has higher wear resistance, corrosion resistance and elastic limit. It is beneficial to further enhance the contact fatigue strength and dimensional stability of the raceway, and can combine the advantages of two different materials. Under different working environment requirements, it can integrate the advantages of each component and make up for the deficiencies, and has comprehensive performance that is difficult to achieve with a single metal or alloy material.

[0036] As a preferred embodiment, the cage 2 described above is an injection-molded structure.

[0037] In the above embodiments, the material of the retainer 2 can be thermoplastic plastics such as polytetrafluoroethylene (PTFE), nylon (PA), polyoxymethylene (POM), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), and polyimide (PI), with polytetrafluoroethylene (PTFE) being preferred.

[0038] In a preferred embodiment, the first contact layer 5 is made of bearing steel, and the inner surface layer 6 is made of aluminum alloy.

[0039] In the above embodiments, bearing steel has high and uniform hardness and wear resistance, as well as a high elastic limit; aluminum alloy is an alloy based on aluminum with a certain amount of other alloying elements added, and is one of the light metal materials; this design can meet the strength and hardness requirements of the bearing during operation, and also reduce the overall weight of the inner ring 3 of the bearing.

[0040] In a preferred embodiment, the second contact layer 7 is made of bearing steel and the outer surface layer 8 is made of titanium alloy.

[0041] In the above embodiments, titanium alloy refers to a variety of alloy metals made of titanium and other metals; this design selects bearing steel as the material of the second contact layer 7 and titanium alloy as the outer layer 8. When working in humid atmospheric and seawater media, its corrosion resistance is far superior to stainless steel; it has particularly strong resistance to pitting corrosion, acid corrosion and stress corrosion; and it has excellent corrosion resistance to alkalis, chlorides, chlorinated organics, nitric acid, sulfuric acid and other substances.

[0042] In a preferred embodiment, the material of the rolling element 1 is a ceramic matrix composite material.

[0043] In the above embodiments, ceramic matrix composite material is a type of composite material with ceramic as the matrix and various fibers. This design makes the rolling element 1 have excellent properties such as high temperature resistance, high strength and rigidity, relatively light weight and corrosion resistance. In addition, the rolling element 1 is prepared by powder metallurgy and is preferably suitable for ball bearings.

[0044] In a preferred embodiment, when the inner ring 3 rotates and the outer ring 4 is fixed, the first contact layer 5 and the inner surface layer 6 are both annular rings of uniform thickness. The surface of the second contact layer 7 that contacts the outer surface layer 8 protrudes to form a first arc-shaped member 9. The outer surface layer 8 is provided with a first inner groove 10 in cooperation with the first arc-shaped member 9.

[0045] In this design, the first arc-shaped component 9 and the second contact layer 7 are integrally formed. The first arc-shaped component 9 and the first inner groove 10 cooperate to form a contact surface. To ensure load bearing capacity, the central axis of this contact surface forms a 90-degree angle with the central axis of the outer ring 4. During manufacturing, it is only necessary to obtain the contact line between the second contact layer 7 and the outer surface layer 8 in the cross-sectional view of the outer ring 4, and then obtain the contact surface by matching the width value of the outer ring 4. The curvature of this contact line determines the specific shape of the first contact layer 5 and the outer surface layer 8. Personnel can design this contact line according to the load distribution law. The specific design principle is as follows:

[0046] For a rigidly supported bearing under radial load, the angular range of the load region determined by the radial clearance is:

[0047]

[0048] In the formula, δ r P is the radial displacement of the collar at ψ = 0°. d This is the radial clearance. At the angular position ψ, the radial displacement of rolling element 1 is...

[0049]

[0050] Where, δ max For the maximum radial displacement, the load distribution range parameter ε is:

[0051]

[0052] For zero clearance, ε = 0.5; for positive clearance, 0 < ε < 0.5; for negative clearance or interference fit, 0.5 < ε < 1.

[0053] Under radial load, the static equilibrium relationship of the bearing can be obtained:

[0054]

[0055] In the formula, for ball bearings, n = 3 / 2, and for roller bearings, n = 10 / 9. K n Stiffness coefficient

[0056]

[0057] For steel balls in contact with the raceway, there are

[0058]

[0059] In the formula, i and o correspond to the inner and outer raceways, respectively. ∑ρ is the sum of the curvatures of the inner and outer raceways, and δ... * for

[0060]

[0061]

[0062] e 2 =1-1 / k 2 (9)

[0063]

[0064]

[0065] In the formula, the subscripts x and y represent the directions of the major and minor semi-axis of the contact ellipse, respectively. The equivalent radius in each direction can be defined as follows: for inner raceway contact... For outer raceway contact Among them, D w Let f be the diameter of rolling element 1. i and f o These are the groove curvature coefficients of the inner ring 3 and outer ring 4 raceways, respectively. α is the contact angle, d m It is the diameter of the pitch circle.

[0066] The maximum contact load between rolling element 1 and raceway is

[0067]

[0068] In the formula, J r (ε) is called the radial integral of the load distribution and is a function of ε.

[0069] Among them, F r The radial load received by the bearing is set according to the fatigue load limit of different bearing models when calculating the load distribution.

[0070] The contact load between the j-th ball and the raceway is

[0071]

[0072] For a specific bearing with given clearance and load, equation (4) can be solved using a trial-and-error method to control the error. First, assume δ r The value of is then used to calculate ε using equation (3) to obtain J. r The value of (ε). If equation (4) cannot be satisfied, the above process is repeated, given a new δ. r The value is calculated until the required solution precision is met.

[0073] Furthermore, the second contact layer 7 of the outer ring 4 is designed. According to the load distribution law, at different angular positions ψ, the thickness of the second contact layer 7 is positively correlated with the magnitude of the contact load. Furthermore, by fitting the position points with NURBS curves, a smooth curve is obtained as the contact line of the contact layer.

[0074] The formula for the NURBS curve is:

[0075]

[0076] In the formula, P i These are control points, forming a control polygon, w i It is a weight factor, N i,p (u) is a p-order B-spline basis function defined by a non-periodic and non-uniform set of nodes, which is

[0077]

[0078] Unless otherwise specified, we assume a = 0, b = 1, w i >0.

[0079] In a preferred embodiment, when the inner ring 3 is fixed and the outer ring 4 is rotated, the second contact layer 7 and the outer surface layer 8 are both annular rings of uniform thickness. The surface of the first contact layer 5 that contacts the inner surface layer 6 is concave to form a second concave arc groove, and the outer surface layer 8 is convex relative to the second concave arc groove to form a second arc-shaped part 11.

[0080] In this design, the second arc-shaped component 11 is integrally formed with the first contact layer 5. The second arc-shaped component 11 and the second inner groove 12 cooperate to form a contact surface. To ensure load bearing capacity, the central axis of this contact surface forms a 90-degree angle with the central axis of the outer ring 4. During manufacturing, it is only necessary to obtain the contact line between the first contact layer 5 and the inner surface layer 6 in the cross-sectional view of the inner ring 3, and then obtain the contact surface by matching the width value of the inner ring 3. The curvature of this contact line determines the specific shape of the first contact layer 5 and the inner surface layer 6. Personnel can design this contact line according to the load distribution law. The specific design principle is as follows:

[0081] For a rigidly supported bearing under radial load, the angular range of the load region determined by the radial clearance is:

[0082]

[0083] In the formula, δ r P is the radial displacement of the collar at ψ = 0°. d This is the radial clearance. At the angular position ψ, the radial displacement of rolling element 1 is...

[0084]

[0085] Where, δ max For the maximum radial displacement, the load distribution range parameter ε is:

[0086]

[0087] For zero clearance, ε = 0.5; for positive clearance, 0 < ε < 0.5; for negative clearance or interference fit, 0.5 < ε < 1.

[0088] Under radial load, the static equilibrium relationship of the bearing can be obtained:

[0089]

[0090] In the formula, for ball bearings, n = 3 / 2, and for roller bearings, n = 10 / 9. K n Stiffness coefficient

[0091]

[0092] For steel balls in contact with the raceway, there are

[0093]

[0094] In the formula, i and o correspond to the inner and outer raceways, respectively. ∑ρ is the sum of the curvatures of the inner and outer raceways, and δ... * for

[0095]

[0096]

[0097] e 2 =1-1 / k 2 (twenty four)

[0098]

[0099]

[0100] In the formula, the subscripts x and y represent the directions of the major and minor semi-axis of the contact ellipse, respectively. The equivalent radius in each direction can be defined as follows: for inner raceway contact... For outer raceway contact Among them, D w Let f be the diameter of rolling element 1. i and f o These are the groove curvature coefficients of the inner ring 3 and outer ring 4 raceways, respectively. α is the contact angle, d m It is the diameter of the pitch circle.

[0101] The maximum contact load between rolling element 1 and raceway is

[0102]

[0103] In the formula, J r (ε) is called the radial integral of the load distribution and is a function of ε.

[0104] Among them, F r The radial load received by the bearing is set according to the fatigue load limit of different bearing models when calculating the load distribution.

[0105] The contact load between the j-th ball and the raceway is

[0106]

[0107] For a specific bearing with given clearance and load, equation (4) can be solved using a trial-and-error method to control the error. First, assume δ r The value of is then used to calculate ε using equation (3) to obtain J. r The value of (ε). If equation (4) cannot be satisfied, the above process is repeated, given a new δ. r The value is calculated until the required solution precision is met.

[0108] Furthermore, the first contact layer 5 of the outer ring 4 is designed. According to the load distribution law, at different angular positions ψ, the thickness of the first contact layer 5 is positively correlated with the magnitude of the contact load. Furthermore, by fitting the position points with NURBS curves, a smooth curve is obtained as the contact line of the contact layer.

[0109] The formula for the NURBS curve is:

[0110]

[0111] In the formula, P i These are control points, forming a control polygon, w i It is a weight factor, N i,p (u) is a p-order B-spline basis function defined by a non-periodic and non-uniform set of nodes, which is

[0112]

[0113] Unless otherwise specified, we assume a = 0, b = 1, w i >0.

[0114] In summary, the embodiments of the present invention provide a rolling bearing made of composite material, which has at least the following beneficial effects: both the inner ring 3 and the outer ring 4 of the bearing are made of composite material. This design not only satisfies the rolling element 1 with sufficient strength and hardness, but also has higher wear resistance, corrosion resistance and elastic limit, which is conducive to further enhancing the contact fatigue strength and dimensional stability of the raceway. It can also combine the advantages of two different materials. Under different working environment requirements, it can integrate the advantages of each component, make up for the deficiencies, and has comprehensive performance that is difficult to achieve with a single metal or alloy material.

[0115] The above are merely preferred embodiments of the present invention and are not intended to limit the present 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 rolling bearing made of composite material, characterized in that, The device includes a concentrically arranged inner ring, a rolling assembly, and an outer ring. The rolling assembly includes a cage and a plurality of rolling elements disposed within the cage. The plurality of rolling elements are rolled between the inner ring and the outer ring. The inner ring includes a first contact layer, and an inner surface layer is disposed inside the first contact layer. The outer ring includes a second contact layer, and an outer surface layer is disposed outside the second contact layer. The elastic modulus of the first contact layer is greater than that of the inner surface layer, and the elastic modulus of the second contact layer is greater than that of the outer surface layer. When the inner ring rotates and the outer ring is fixed, the first contact layer and the inner surface layer are both circular rings of uniform thickness. The surface of the second contact layer that contacts the outer surface layer protrudes outward to form a first arc-shaped component. The outer surface layer is provided with a first inner groove relative to the first arc-shaped component. When the inner ring is fixed and the outer ring rotates, both the second contact layer and the outer surface layer are circular rings of uniform thickness. The surface of the first contact layer that contacts the inner surface layer is concave to form a second concave arc groove, and the outer surface layer convexes outward relative to the second concave arc groove to form a second arc-shaped component.

2. The rolling bearing of a composite material according to claim 1, characterized in that, The cage is an injection-molded structure.

3. A rolling bearing made of composite material according to claim 1, characterized in that, The first contact layer is made of bearing steel, and the inner surface layer is made of aluminum alloy.

4. A rolling bearing made of composite material according to claim 3, characterized in that, The second contact layer is made of bearing steel, and the outer surface layer is made of titanium alloy.

5. A rolling bearing made of composite material according to claim 1, characterized in that, The rolling element is made of ceramic matrix composite material.

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