**1 introduction**

spherical plain bearing is a kind of spherical sliding bearing, which is composed of an inner ring with an outer sphere and an outer ring with an inner sphere. Because the contact area of spherical plain bearings is large, the inclination Angle is large, and most spherical plain bearings adopt special process treatment methods, so they have greater load capacity and impact resistance, good aligning performance, and have the characteristics of large bearing capacity and self-aligning. Therefore, spherical plain bearings are widely used in swing motion, tilt motion and rotation motion with low speed.

In this paper, the thermosolid coupling analysis model of spherical plain bearing is established by using finite element method. The influence of ambient temperature on bearing characteristics and the ultimate working load of spherical plain bearing are analyzed.

**2 Finite element analysis modeling method of spherical plain bearing**

In order to implement the same specifications, different sizes, different materials, different working status and related analysis of spherical plain bearing, under different working conditions by using ANSYS with APDL programming language, the establishment of a spherical plain bearing parameterized analysis model, the main parameters for the bearing size, material properties and parameters such as load, oblique Angle and temperature. The finite element parametric modeling of bearings mainly includes the following steps:

(1) Establishment of bearing geometric model.

(2) The influence of temperature should be considered in the analysis.

(3) Finite element model processing.

(4) Setting of load and solution type.

**3 Basic parameters of spherical plain bearings**

Taking a certain spherical plain bearing as an example, the finite element analysis software ANSYS is used to analyze the spherical plain bearing. The spherical plain bearing is mainly composed of an inner ring with an inner sphere, an outer ring with an inner sphere and a PTFE solid lubrication film. The solid lubrication film is bonded to the outer ring.

**4 Azial ultimate load analysis of spherical plain bearing**

The axial limit load of spherical plain bearings at room temperature is mainly analyzed, and the radial load is taken as 0 and 931kN. By analyzing the variation of bearing stress with axial load, the axial ultimate load corresponding to the maximum stress of bearing can be obtained according to the material parameters of bearing.

## 4.1 Axial limit load analysis without radial load

When the radial load is 0, the axial load ranges from 0 to 280kN in order to solve the axial limit load of the spherical plain bearing. FIG. 2 shows the deformation, displacement and stress distribution of the spherical plain bearing under an axial load of 160kN without radial load. According to Figure 2a, under the action of axial load, the deformation displacement of the bearing is mainly the axial displacement of the inner ring. As can be seen from FIG. 2b, 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. As can be seen from FIG. 2c, the maximum equivalent stress of the bearing is located on the outer surface of the outer ring, close to the side, and evenly distributed along the circumference, 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 close to the side of the spherical surface and evenly distributed along the circumference.

When there is no radial load, the maximum equivalent stress, maximum contact stress and maximum shear stress of bearings under different axial loads. It can be seen from the table that when the axial load changes under 0~280kN, the maximum stress of the bearing changes.

Change curve of maximum stress value of bearing with axial load without radial load. The bearing stress includes the maximum equivalent stress, the maximum contact stress and the maximum shear stress. As can be seen from the figure, when the axial load is from 28.9kN to 278kN, the maximum stress of the bearing rises linearly: the maximum equivalent stress increases from 45.07Mpa to 454.1MPa; The maximum contact stress increased from 43.6MPa to 442.4MPa. The maximum shear stress increased from 15.98MPa to 158.33MPa.

By using the variation law of the maximum stress of the bearing, the influence of axial load on bearing characteristics of the spherical plain bearing without radial load can be obtained. According to the material properties of the inner and outer rings, such as yield strength, the axial load corresponding to the maximum stress of the bearing at yield can be obtained, that is, the axial limit load of the bearing.

## 4.2 Axial limit load analysis when the 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 of the axial load ranges from 0 to 170kN. Deformation, displacement and stress distribution of spherical plain bearing under axial load of 167kN. It can be seen from FIG. 4a that under the combined action of axial and radial loads, the maximum deformation displacement of the bearing is on both sides under the bearing (i.e., the main bearing area). As can be seen from Figure 4b, the maximum contact stress of the bearing is located near the side of the spherical surface in the main bearing area. As can be seen from FIG. 4c, the maximum equivalent stress of the bearing is located on the inner surface of the inner ring near the maximum contact stress in the main bearing area, indicating that this position is the main bearing area at this time. According to FIG. 4d, in 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 on both sides of the maximum equivalent stress position in the bearing area, and the maximum shear compressive stress is in the middle of the non-bearing area and bearing area.

Is the maximum equivalent stress, maximum contact stress and maximum shear stress of bearings under different axial loads when the radial load is 931kN. It can be seen from the table that when the axial load changes under 0~280kN, the maximum stress of the bearing changes.

When the radial load is 931kN, the maximum stress value of the bearing changes with the axial load curve. The bearing stress includes the maximum equivalent stress, the maximum contact stress and the maximum shear stress. When the axial load is from 20kN to 166.75kN:

(1) The maximum equivalent stress first decreased slowly and then increased sharply: When the load increases from 20kN to 118.67kN, the maximum equivalent stress decreases from 389.86MPa to 387.99MPa with a decrease of 0.5%. When the load increases from 118.67kN to 166.75kN, the maximum equivalent stress decreases from 387.99MPa to 446.09MPa with an increase of 13%.

(2) The equivalent stress of the maximum contact stress gradually increases, and the increasing speed 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 with an increase of 6.5%. When the load increases from 118.67kN to 166.75kN, the maximum equivalent stress increases from 337.29MPa to 437.56MPa. That’s a 22.8 percent increase.

(3) The maximum shear stress of the bearing has a small change, which slowly increases from 137.84MPa to 141.67MPa, with an increase of 2.7%.

By using the variation law of the maximum stress of the bearing, the influence trend of axial load on the maximum stress of the spherical plain bearing can be obtained when the radial load is 931kN. Thus, the axial ultimate load corresponding to the maximum stress when the bearing reaches yield is obtained.

**5 conclusion**

This paper mainly analyzes the axial limit load of bearings under different working conditions.

By APDL language can build complete finite element parametric model of spherical plain bearing, will need to change the parameter is set to variable, controlled through processing and solving process of the model, can implement different spherical plain bearings under different working condition and working environment of correlation analysis, get load-bearing characteristics of spherical plain bearing, the contact characteristic and dynamic characteristic, etc., And the influence of various factors on bearing characteristics.