A method for improving thermal-elastic deformation of a thrust slide bearing by modifying the shape

Abstract

The application discloses a method for improving thermal elastic deformation of a thrust sliding bearing, which takes the center position (x0, y0) of a pad as the position of the maximum value of the modification depth, and forms the thrust sliding bearing after the pad surface is geometrically modified. The application provides a method for improving thermal elastic deformation of a thrust sliding bearing, solves the problems of the reduction of bearing load area and the deterioration of lubrication performance caused by the thermal elastic deformation of the pad, and guarantees the stable and reliable operation of the thrust sliding bearing.

Description

Technical Field

[0001] This invention belongs to the field of sliding bearing technology, and specifically relates to a shaping method for improving the thermoelastic deformation of thrust sliding bearings. Background Technology

[0002] Thrust sliding bearings, due to their advantages such as high load-bearing capacity, high reliability, low noise, and long service life, are widely used in large rotating units such as hydraulic turbines as core components bearing axial loads, and have a significant impact on the performance of the equipment. With the continuous development of technology, the operating conditions of rotating machinery are moving towards high speed and heavy load. Under these harsh conditions, improving the reliability and stability of thrust sliding bearings has become a major concern for engineers. For large thrust bearings, under heavy load conditions, the oil film pressure and temperature rise of the bearing pads are large, and the heat conduction rate of the pads is limited, resulting in significant elastic and thermal deformation of the pads. This causes abnormal phenomena such as upward bending of the bearing pad edges and bulging of the center of the pads. Typically, thermal elastic deformation leads to a reduction in the effective bearing area, greatly deteriorating the lubrication performance of the thrust bearing.

[0003] Currently, there are no methods in industry to improve the thermoelastic deformation of thrust sliding bearings. Current methods mainly involve increasing the area or number of bearing pads to ensure the bearing's load-bearing capacity and lubrication performance. However, these methods are difficult to implement due to limitations in equipment structure and economic costs. Therefore, it is necessary to propose methods to improve the thermoelastic deformation of thrust sliding bearings. Summary of the Invention

[0004] The purpose of this invention is to provide a method for improving the thermoelastic deformation of thrust sliding bearings. In response to the problem that the bearing pads of thrust sliding bearings bulge upwards under heavy load conditions, resulting in a reduction in bearing area and severe deterioration of lubrication performance, this invention proposes a method to improve the bearing area reduction caused by thermoelastic deformation by modifying the upper surface of the thrust sliding bearing.

[0005] The present invention is achieved using the following technical solution:

[0006] A method for improving the thermoelastic deformation of a thrust sliding bearing is proposed. This method takes the center position (x0, y0) of the tile as the position where the maximum shaping depth is located. After the surface of a single tile is geometrically shaped, a thrust sliding bearing is formed.

[0007] A further improvement of this invention is that the upper surface of a single tile is shaped according to the following equation:

[0008]

[0009] In the formula, h m h is the height of the bearing shell after the reshaping, and h is the height of the bearing shell before the reshaping.d For the maximum shaping depth, f(x) and f(y) are cubic shaping equations, where x and y are the surface equations of the bearing, expressed as follows:

[0010]

[0011] Where r1 is the inner diameter of the tile, r2 is the outer diameter of the tile, α is the wrap angle of the tile, x = ρcosθ, y = ρcosθ.

[0012] A further improvement of the present invention is that the maximum shaping depth h of the tile is... d It consists of two parts: elastic deformation and thermal deformation, and its calculation formula is shown in the following equation:

[0013] h d =max(max({ε M})+max({ε T})) (3)

[0014] In the formula, {ε M} is the elastic deformation matrix, {ε T} represents the thermal deformation matrix.

[0015] A further improvement of this invention is that the elastic deformation matrix of the tile is solved simultaneously by the following equations:

[0016]

[0017]

[0018]

[0019] In the above equation, u, v, and w are the velocity field equations of the thrust sliding bearing, and f x f y and f z Let {σ} represent the through-body forces acting on a unit volume of fluid in the x, y, and z directions, respectively, where {σ} is the stress matrix and {ε} is the stress matrix. M {D} is the mechanical strain matrix, which is also the elastic deformation matrix that we ultimately need to solve for, and {D} is the elastic material constant matrix, calculated using the following formula:

[0020]

[0021] In the formula, ν is Poisson's ratio, and E is the elastic modulus of the bearing material;

[0022] Combine (3) and (4), express {σ} using the derivatives of u, v and w, solve equation (5) to calculate the expressions for u, v and w, and calculate the elastic deformation matrix {ε} according to equation (3).

[0023] A further improvement of this invention is that the formula for calculating the thermal deformation of the tile is:

[0024]

[0025] In the formula, β is the bearing thermal expansion coefficient, and ΔT is the bearing oil film temperature rise.

[0026] A further improvement of this invention lies in that the bearing oil film temperature rise ΔT is obtained by numerically calculating the Reynolds equation and the energy equation to obtain the bearing oil film temperature rise distribution; the Reynolds equation is shown below:

[0027]

[0028] In the formula, h is the oil film thickness, ω is the rotational speed, r is the bearing radius, μ is the lubricating oil viscosity, θ is the circumferential position angle, ρ is the lubricating oil density, and p is the oil film pressure.

[0029] A further improvement of this invention is that the energy equation is as follows:

[0030]

[0031] In the formula C p denoted as , where is the specific heat capacity of the lubricating oil, and k is the thermal conductivity of the lubricating oil.

[0032] A further improvement of this invention is that the temperature boundary conditions of the energy equation are calculated according to the following heat conduction equation:

[0033]

[0034] In the formula, T(x,y,z,t) is the oil film temperature rise equation, and Q(x,y,z) is the generation heat equation.

[0035] The present invention has at least the following beneficial technical effects:

[0036] 1) This invention provides a method for improving the thermoelastic deformation of thrust sliding bearings. By geometrically modifying the surface of the bearing pads, the problem of reduced bearing area and deteriorated lubrication performance caused by thermoelastic deformation of the bearing pads is solved, thus ensuring the stable and reliable operation of the thrust sliding bearing.

[0037] 2) Compared with traditional improvement methods, the present invention does not require changes to the external dimensions of the bearing or an increase in the number of bearing pads, making it easy to implement and economical. Attached Figure Description

[0038] Figure 1 These are comparison images of the tile before and after thermoelastic deformation. Figure 1 (a) before thermoelastic deformation Figure 1 (b) After thermoelastic deformation.

[0039] Figure 2 This is a diagram showing the parameters of the tile.

[0040] Figure 3 This is a schematic diagram of tile reshaping, in which... Figure 3 (a) is the modified bearing shell. Figure 3 (b) is Figure 3 Section A in (a) Figure 3 (c) is Figure 3 (a) is the B section view.

[0041] Figure 4 The distribution of membrane pressure, membrane thickness, and membrane temperature of the thrust sliding bearing before shaping.

[0042] Figure 5 The distribution of membrane pressure, membrane thickness, and membrane temperature in the thrust sliding bearing after modification. Detailed Implementation

[0043] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] like Figure 1 As shown, under heavy load conditions, the thermoelastic deformation of the thrust sliding bearing pads causes abnormal phenomena such as the bearing pad edges bending upwards and the pad center bulging. This greatly reduces the bearing load area and deteriorates the bearing lubrication performance. The present invention provides a method for modifying the shape of the thrust sliding bearing pads to improve this phenomenon.

[0045] The parameters of the tile are as follows Figure 2 As shown, the characteristic of the tile reshaping method is that the center position (x0, y0) of the tile is taken as the location of the maximum reshaping depth, such as... Figure 3 As shown, the upper surface of a single tile is shaped according to the following equation:

[0046]

[0047] Among them, h m h is the height of the bearing shell after the reshaping, and h is the height of the bearing shell before the reshaping. d For the maximum shaping depth, f(x) and f(y) are cubic shaping equations, where x and y are the surface equations of the bearing, expressed as follows:

[0048]

[0049] Where r1 is the inner diameter of the tile, r2 is the outer diameter of the tile, α is the wrap angle of the tile, x = ρcosθ, y = ρcosθ.

[0050] Maximum shaping depth h of the tile d It consists of two parts: elastic deformation and thermal deformation. The calculation formula is shown below:

[0051] h d =max(max({ε M})+max({ε T})) (3)

[0052] Where, {ε M} is the elastic deformation matrix, {ε T} represents the thermal deformation matrix.

[0053] The elastic deformation matrix of the tile can be solved by solving the following equations simultaneously:

[0054]

[0055]

[0056]

[0057] Where u, v, and w are the velocity field equations of the thrust sliding bearing, and f x f y and f z Let {σ} represent the through-body forces acting on a unit volume of fluid in the x, y, and z directions, respectively, where {σ} is the stress matrix and {ε} is the stress matrix. M {D} is the mechanical strain matrix, which is also the elastic deformation matrix that we ultimately need to solve for, and {D} is the elastic material constant matrix, calculated using the following formula:

[0058]

[0059] Where ν is Poisson's ratio and E is the elastic modulus of the bearing material.

[0060] By combining equations (3) and (4), and expressing {σ} in terms of the derivatives of u, v, and w, we can solve equation (5) to calculate the expressions for u, v, and w. Then, we can calculate the elastic deformation matrix {ε} according to equation (3).

[0061] The formula for calculating the thermal deformation of the tile is:

[0062]

[0063] In the formula, β is the bearing thermal expansion coefficient, and ΔT is the bearing oil film temperature rise.

[0064] The bearing oil film temperature rise ΔT was calculated using numerical methods by solving the Reynolds equation and the energy equation to obtain the bearing oil film temperature rise distribution. The Reynolds equation is shown below:

[0065]

[0066] in, h is the oil film thickness, ω is the rotational speed, r is the bearing radius, μ is the lubricating oil viscosity, θ is the circumferential position angle, ρ is the lubricating oil density, and p is the oil film pressure.

[0067] The energy equation is shown below:

[0068]

[0069] Where C p denoted as , where is the specific heat capacity of the lubricating oil, and k is the thermal conductivity of the lubricating oil.

[0070] The temperature boundary conditions for the energy equation are calculated according to the following heat conduction equation:

[0071]

[0072] Where T(x,y,z,t) is the oil film temperature rise equation, and Q(x,y,z) is the generation heat equation.

[0073] After the pad is shaped, it undergoes thermo-elastic deformation. The concave surface expands and the center bulges upward, the edge of the pad bends upward, and the concave surface deforms into a flat surface. The pad does not reduce the bearing area due to thermo-elastic deformation, effectively ensuring the lubrication performance of the thrust sliding bearing.

[0074] Example

[0075] To demonstrate the superiority of the present invention, a thrust sliding bearing was selected, and the basic parameters and operating parameters of the bearing are shown in Table 1.

[0076] Table 1 Bearing and Operating Condition Parameters

[0077]

[0078]

[0079] The pressure distribution, film thickness distribution, temperature distribution, and elastic deformation distribution of the thrust sliding bearing before and after the modification are as follows: Figure 4 and Figure 5 As shown in the figure, the minimum oil film thickness of the thrust sliding bearing before modification is 2.08 μm, and the minimum oil film thickness after modification is 2.92 μm, which is almost 50% thicker, thus improving the lubrication performance of the thrust sliding bearing.

[0080] In summary, this invention provides a method for improving the thermoelastic deformation of thrust sliding bearing pads. The maximum thermoelastic deformation value of the pad under typical operating conditions is obtained through numerical calculation as the maximum shaping depth. Then, the center of the pad is selected as the location of the maximum shaping depth to shape the entire pad. After shaping, the pad, after thermoelastic deformation, essentially remains a flat plane during operation, ensuring the bearing's load-bearing area. Compared with traditional methods, this method is not limited by bearing size and does not require increasing the number of pads. It is easy to implement, economical, and effectively solves the problem of reduced bearing area and deteriorated bearing lubrication performance caused by thermoelastic deformation of thrust sliding bearings under heavy load conditions, ensuring bearing stability and service life.

Claims

1. A method for improving the thermoelastic deformation of a thrust sliding bearing, characterized in that, This method takes the center position of the tile ( x 0, y 0) At the location of the maximum shaping depth, the surface of a single tile is geometrically shaped to form a thrust sliding bearing; The upper surface of a single tile is shaped according to the following equation: (1) In the formula, h m The height of the bearing shell after modification. h To modify the height of the front axle bearing, h d For maximum shaping depth, f(x) and f(y) It is a 3rd degree modified equation. x , y The equation for the bearing surface is given by the following formula: (2) in, r 1 represents the inner diameter of the tile. r 2 represents the outer diameter of the tile. α For the corner of the tile, x = ρ cos θ , y = ρ cos θ ; Maximum shaping depth of the tile h d It consists of two parts: elastic deformation and thermal deformation, and its calculation formula is shown in the following equation: (3) In the formula, For elastic deformation matrix, This is the thermal deformation matrix; The elastic deformation matrix of the tile can be solved by solving the following equations simultaneously: (4) (5) (6) In the above formula, u , v and w The velocity field equation for a thrust sliding bearing is... f x , f y and f z The force exerted on a unit volume of fluid, respectively x , y and z Directional penetrating force, { σ } is the stress matrix, { ε M } is the mechanical strain matrix, which is also the elastic deformation matrix that we ultimately need to solve for. D Let} be the matrix of elastic material constants, calculated using the following formula: (7) In the formula, ν Poisson's ratio, E The elastic modulus of the bearing material; Combine (3) and (4), and we can form { σ }use u , v and w The derivative of the expression is used to solve equation (5) to calculate the result. u , v and w The expression is given, and the elastic deformation matrix is ​​calculated according to equation (3). }; The formula for calculating the thermal deformation matrix of the tile is: (8) In the formula, β This refers to the coefficient of thermal expansion of the bearing. ΔT This refers to the temperature rise of the bearing oil film.

2. The method for improving the thermoelastic deformation of a thrust sliding bearing according to claim 1, characterized in that, Bearing oil film temperature rise ΔT The oil film temperature rise distribution of the bearing was obtained by solving the Reynolds equation and the energy equation using numerical calculation methods. The Reynolds equation is shown below: (9) In the formula, , , , h For oil film thickness, ω For rotational speed, r For the bearing radius, μ The viscosity of the lubricating oil. θ The circumferential position angle, ρ For the density of lubricating oil, p This refers to the oil film pressure.

3. The method for improving the thermoelastic deformation of a thrust sliding bearing according to claim 2, characterized in that, The energy equation is shown below: (10) In the formula C p The specific heat capacity of lubricating oil, k This refers to the thermal conductivity of the lubricating oil.

4. The shaping method for improving the thermoelastic deformation of a thrust sliding bearing according to claim 3, characterized in that, The temperature boundary conditions for the energy equation are calculated according to the following heat conduction equation: (11) In the formula T(x,y,z,t) The equation for oil film temperature rise is as follows: Q(x,y,z) To generate the thermal equation.

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