Structural optimization of radial spherical plain bearings
As a general-purpose component, the spherical segment bearing has the characteristics of flexible rotation, compact structure, easy assembly and disassembly, etc. It can meet the requirements of heavy load and long service life, and has been widely used in mining, metallurgy, electric power, transportation, aerospace and textiles. Mechanical equipment . my country's research on spherical plain bearings and the corresponding industrial production started relatively late, generally by referring to foreign data or based on actual experience to determine the relevant technical numbers, lack of scientific basis. Based on this, we use the large-scale finite element analysis software ANSYS to carry out finite element analysis on the radial spherical plain bearing GEZ101ES. Under the condition that other parameters related to the assembly remain unchanged, the spherical diameter of the spherical plain bearing is optimized to make the radial spherical plain bearing. The distribution of the stress on the spherical plain bearing is more reasonable, so as to realize the optimal design and improve the life of the spherical plain bearing . Experimental part 1 Structural optimization ANSYS program is a large-scale general finite element analysis software with powerful functions, which integrates design analysis and optimization. Before the design scheme is adopted or put into production, the optimization design function of the ANSYS program can be used to accurately find out its potential design defects or determine the optimal geometric shape, shorten the development cycle of multiple machine manufacturing, testing and manufacturing, and reduce production costs. . The radial spherical plain bearing developed by Fujian Longxi Bearing Co., Ltd. through the introduction of foreign technology is selected as the research object. The density is 7.8 g/cm. , the tensile strength is 2 155 MPa, and the compressive strength is 3 725 MPa. Figure 1 shows the schematic diagram of the GEZ101ES radial spherical plain bearing. To make the simulation more realistic, an axis is introduced inside the model. Since the radial spherical plain bearing has the characteristics of structural symmetry, only 1/4 of the overall structure is used for simulation when creating the finite element structure model. The finite element analysis of the spherical plain bearing adopts solid modeling, and uses the solid element SOLID92 with 10 nodes of tetrahedron, which has three degrees of freedom in , Y, z, etc. It is suitable for the simulation of irregular geometric shapes, and the calculation accuracy is high. The number of nodes and mesh elements generated during free meshing can be different; the finite element meshing is denser, so that the stress concentration area of u200bu200bthe radial spherical plain bearing can be displayed more clearly. The GEZ101ES radial spherical plain bearing is a steering multi-function bearing, and the stress situation is more complicated, so it must be simplified in the finite element analysis. Since the radial load is the main factor affecting the bearing capacity and service life of the GEZ101ES radial spherical plain bearing, the radial load effect is mainly considered; and under the service conditions of the spherical plain bearing, the rate of rotation or swing is funded and; the aviation science fund funded project ( 04G52044). Very slow, in most cases no more than 6 revolutions per minute (swing times), so the quasi-static model can be used for finite element analysis of spherical plain bearings. At the same time, the spherical plain bearing has a symmetrical structure. In order to reduce the calculation amount, ANSYS stipulates that 1/4 of the overall structure can be used for calculation. Taking the ball diameter of GEZ101ES as the reference size, the changes in the ball diameter are taken as 0, +0.5 mm, +1.0 mm, +1.5 mm, -0.5 mm, and -1.0 mm. , a 1.25 mm, a 1.5 mm (0 means the original size remains unchanged, a positive sign means an increase in size, and a negative sign means a reduction in size), and solve them separately. Since the spherical plain bearing is subjected to compressive stress under service conditions, the failure is due to the contact fatigue under the action of the compressive stress, so this paper mainly calculates the maximum compressive stress on the bearing; The diameter of the ball is used to calculate the change of the maximum compressive stress on the bearing. Fig. 2 shows the D change quantity/ram of the GEZ101ES centripetal joint. Fig 2 The 3rd primary stress s. variation ofspherical diameter for GEZ101ESFig.2 The relationship curve of compressive stress with the change of the bearing ball diameter The relationship curve of the absolute value of the third principal stress 0'3 of the bearing (ie the maximum compressive stress) with the change of the ball diameter D. It can be seen that , the maximum compressive stress on the spherical plain bearing is closely related to the change of the size of the ball diameter. When the size of the spherical diameter increases from 0.0 mm to 1.5 mm, the maximum compressive stress on the spherical plain bearing increases greatly; When the size decreases from 0.0 mm to -1.5 mm, the maximum compressive stress fluctuates, which depends on the structural nonlinearity. When the size reduction of the ball diameter is 1.0 mm, the maximum compressive stress on the spherical plain bearing The minimum. The material of the radial spherical plain bearing is quenched and low-temperature tempered GCrl5 steel, and its structure is tempered martensite, which is a brittle material, so the first strength theory or the second strength theory should be used for checking. In view of the first strength The theoretical form is simple and does not affect the calculation results, so this paper adopts the first strength theory for checking, ie ≤[ ], or ≤[ v] ( . is the first principal stress, . is the third principal stress). When the original data remains unchanged (the change in UP is 0 mm), the overall maximum compressive stress of the bearing (the maximum value of the absolute value of the third principal stress 0'3rain) is l. Blood l-1 623.4 MPa; and when the size of the ball diameter is reduced by 1 mm, the overall maximum compressive stress of the bearing is 1 150.1 MPa. It can be seen that when the size of the ball diameter is reduced by 1.0 mm, the maximum compressive stress on the bearing is reduced from the original 1 623.4 MPa to 1 150.1 MPa. Therefore, the diameter of the radial spherical plain bearing GEZ101ES is reduced by 1.0 mm to determine the optimal value.