1 Introduction
A spherical plain bearing is a spherical plain bearing, which consists of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface. Because the contact area of the spherical plain bearing is large, the inclination angle is large, and most of the spherical plain bearings adopt special processing methods, so they have a large load capacity and impact resistance, good self-aligning performance, and have large load capacity and self-alignment. Features. Therefore, spherical plain bearings are widely used for low-speed oscillating motion, tilting motion and rotational motion.
This paper mainly uses the finite element method to establish the thermo-solid coupling analysis model of the spherical plain bearing, and analyzes the influence of the working environment temperature on its bearing characteristics and the limit working load of the spherical plain bearing.
2 Finite element analysis and modeling method of spherical plain bearing
In order to facilitate the analysis of spherical plain bearings under the same specifications, different sizes, different materials, different working states and different working conditions, this paper uses the APDL programming language that comes with ANSYS.
The parametric analysis model of spherical plain bearing is established, in which the main parameters are bearing size, material properties, load, deflection angle and temperature. The finite element parametric modeling of bearings mainly includes the following steps:
(1) The establishment of bearing geometric model.
(2) The influence of temperature needs to be considered in the analysis.
(3) Finite element model processing.
(4) Setting of load and solution type.
3 Basic parameters of spherical plain bearings
Now take a joint bearing as an example, use the finite element analysis software ANSYS to analyze the joint bearing. Figure 1 is a schematic diagram of the joint bearing.
Fig. 1 Schematic diagram of spherical plain bearing
As shown in Figure 1, the spherical plain bearing is mainly composed of an inner ring with an outer spherical surface, an outer ring with an inner spherical surface and a PTFE solid lubricating film. The solid lubricating film is bonded to the outer ring, and the dimensional parameters of the bearings are shown in Table 1.
Table 1 Dimensional parameters of spherical plain bearings (mm)
4 Analysis of axial limit load of spherical plain bearing
The axial limit load of the spherical plain bearing at room temperature is mainly analyzed, and the radial load is taken as two working conditions of 0 and 931kN respectively. By analyzing the change of bearing stress with axial load, the axial limit load corresponding to the maximum stress of the bearing can be obtained according to the material parameters of the bearing.
4.1 Analysis of axial limit load without radial load
When the radial load is 0, in order to solve the axial limit load of the spherical plain bearing, the value range of the axial load is 0~280kN. Figure 2 shows the deformation displacement and stress distribution of the spherical plain bearing when the axial load is 160 kN without radial load. It can be seen from Fig. 2a that under the action of axial load, the deformation displacement of the bearing is mainly the axial displacement of the inner ring. It can be seen from Figure 2b that the maximum shear stress of the bearing is located on the outer ring of the bearing, and the maximum values of shear tensile stress and shear compressive stress are equal and symmetrically distributed. It can be seen from Figure 2c that the maximum equivalent stress of the bearing is located on the outer surface of the outer ring, close to the side surface, and is evenly distributed along the circumferential direction, indicating that this position is the main bearing area of the bearing at this time. It can be seen from Fig. 2d that the maximum contact stress of the bearing is at the position where the spherical surface is close to the side and is evenly distributed along the circumferential direction.
Fig. 2 Deformation and stress distribution of bearing without radial load
(Axial load: 160kN)
Table 2 shows the maximum equivalent stress, maximum contact stress and maximum shear stress of the bearing under different axial loads when there is no radial load. It can be seen from the table that when the axial load changes from 0 to 280kN, the change of the maximum stress of the bearing.
Table 2 Bearings under different axial loads
Maximum stress value (radial load: 0kN)
Figure 3 shows the change curve of the maximum stress value of the bearing with the axial load when there is no radial load. The stress of the bearing includes the maximum equivalent stress, the maximum contact stress and the maximum shear stress. It can be seen from the figure that when the axial load is from 28.9kN to 278kN, the maximum stress of the bearing increases linearly: the maximum equivalent stress increases from 45.07Mpa to 454.1MPa; the maximum contact stress increases from 43.6MPa to 442.4MPa; the maximum shear stress increases from 15.98 MPa increased to 158.33MPa.
Fig. 3 Maximum stress of bearing without radial load
Value as a function of axial load
Using the variation law of the maximum stress of the bearing, the influence of the axial load on the bearing characteristics of the spherical plain bearing can be obtained when there is no radial load. According to the material properties of the inner and outer rings, such as yield strength, etc., the axial load corresponding to the maximum stress when the bearing reaches yield can be obtained, that is, the axial limit load of the bearing.
4.2 Analysis of axial limit load when radial load is 931kN
When the radial load is 931kN, in order to solve the axial limit load of the spherical plain bearing, the value range of the axial load is 0~170kN. Figure 4 shows the deformation displacement and stress distribution of the spherical plain bearing when the axial load is 167kN. It can be seen from Fig. 4a that under the combined action of axial load and radial load, the maximum deformation displacement of the bearing is located on both sides of the lower part of the bearing (that is, the main load-bearing area). It can be seen from Fig. 4b that the maximum contact stress of the bearing is located in the main bearing area where the spherical surface is close to the side. It can be seen from Figure 4c that the maximum equivalent stress of the bearing is on the inner surface of the inner ring, which is located in the main load-bearing area close to the maximum contact stress, indicating that this position is the main load-bearing area of the bearing at this time. It can be seen from Figure 4d that among the maximum shear stress of the bearing, the shear tensile stress is significantly larger than the shear compressive stress, the maximum shear tensile stress is located on both sides of the maximum equivalent stress position in the bearing area, and the maximum shear compressive stress is in the non-load bearing area. and the middle of the bearing area.
Fig. 4 The deformation and stress distribution of the bearing when the radial load is 931kN
(Axial load: 167kN)
Table 3 shows the maximum equivalent stress, maximum contact stress and maximum shear stress of the bearing under different axial loads when the radial load is 931kN. It can be seen from the table that when the axial load changes from 0 to 280kN, the change of the maximum stress of the bearing.
Table 3 Maximum bearing capacity under different axial loads
Stress value (radial load: 931kN)
Figure 5 shows the change curve of the maximum stress value of the bearing with the axial load when the radial load is 931kN. The stress of the bearing includes the maximum equivalent stress, the maximum contact stress and the maximum shear stress. It can be seen from the figure that when the axial load is from 20kN to 166.75kN:
(1) The maximum equivalent stress first decreases slowly and then increases sharply:
When the load increased from 20kN to 118.67kN, the maximum equivalent stress decreased from 389.86MPa to 387.99MPa, and the decrease was 0.5%. When the load increased from 118.67kN to 166.75kN, the maximum equivalent stress decreased from 387.99MPa to 387.99MPa. 446.09MPa, an increase of 13%.
(2) The equivalent stress of the maximum contact stress increases gradually, and the speed of increase is from slow to fast: when the load increases from 20kN to 118.67kN, the maximum equivalent stress increases from 315.28MPa to 337.29MPa, an increase of 6.5%. When 118.67kN increased to 166.75kN, the maximum equivalent stress increased from 337.29MPa to 437.56MPa, an increase of 22.8%.
(3) The change of the maximum shear stress of the bearing is small, which is determined by
Fig. 5 The maximum bearing capacity when the radial load is 931kN
Variation curve of stress value with axial load
137.84MPa slowly increased to 141.67MPa, an increase of 2.7%. Using the variation law of the maximum stress of the bearing, when the radial load is 931kN, the influence trend of the axial load on the maximum stress of the spherical plain bearing can be obtained. From this, the axial limit load corresponding to the maximum stress at which the bearing reaches yield is obtained.
5 Conclusion
This paper mainly analyzes the axial limit load of the bearing under different working conditions. Through the APDL language, a complete finite element parametric model of the spherical plain bearing can be established, the parameters that need to be changed are set as variables, and by controlling the model processing and solution process, different spherical plain bearings can be realized in different working states and different working environments According to the relevant analysis below, the bearing characteristics, contact characteristics and dynamic characteristics of the spherical plain bearing are obtained, as well as the influence of various factors on the bearing characteristics.
6 More about VAFEM Spherical Plain Bearings
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2022-09-15