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Spherical steel bearing

Spherical steel bearing

  • Category:Traffic Engineering Rubber Products
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  • Release time:2022-10-21 11:10:44
  • Product description

1. Product introduction


The application of basin-type rubber bearings has promoted the progress of bridge technology in my country, and has become the main bearing type of long-span highway and railway bridges in my country. However, with the construction of a large number of high-grade highways in my country and the construction of a large number of urban overpasses and viaducts, a new type of bridge bearing that is more flexible in rotation and can adapt to curved bridges and inclined bridges—spherical steel bearings is needed.


QZ series spherical steel bearings strictly follow the national standard GB/T 17955-2000 "Technical Conditions for Spherical Bearings" of the People's Republic of China, and also refer to the structure bearings issued by the European Committee for Standardization CEN/TC 167 Technical Committee in August 1993 Draft Standard Part VII "Spherical and Cylindrical PTFE Bearings" and Part II "Sliding Parts", British Standard BS 5400 "Steel Bridges, Concrete Bridges and Combined Bridges" Part Nine "Bridge Bearings" Regulation.


2. Code


Example: QZ20000SX—e±100—θ0.02, which means a two-way movable spherical steel bearing with a design vertical bearing capacity of 20,000kN, a displacement of ±100mm, and a rotation angle of 0.02rad.


3. Structure and working principle


The spherical steel support is composed of an upper support plate (including stainless steel plate), a lower support plate, a spherical plate and a polytetrafluoroethylene sliding plate (one planar and one spherical, hereinafter referred to as PTFE plate).


The structure diagram of the two-way movable spherical steel bearing (code SX) is shown in Figure 1;


The structure diagram of the one-way movable spherical steel bearing (code DX) is shown in Figure 2;


The structure of the fixed spherical steel bearing (code GD) is shown in Figure 3.

The displacement of the spherical steel support is realized by sliding between the upper support plate and the plane PTFE slide. By adding guide grooves or guide rings on the upper support plate to constrain the one-way or multi-directional displacement of the support, the one-way movable support and fixed support of the spherical steel support can be made.


The spherical steel support meets the needs of the support corner through the sliding between the spherical plate and the spherical PTFE slide.


Fourth, the characteristics of the support


The spherical steel bearing has reliable force transmission and flexible rotation. It not only has the characteristics of large bearing capacity and large displacement of the basin rubber bearing, but also can better adapt to the need for a large rotation angle of the bearing. Compared with the pot bearing, it has the following characteristics:


1. The spherical steel bearing transmits the force through the spherical surface, so there is no force necking phenomenon, and the reaction force acting on the concrete is relatively uniform;


2. The spherical steel support realizes the rotation process of the support through the sliding of the spherical PTFE slide plate, so the rotational torque is small, and the rotational torque is only related to the radius of curvature of the spherical surface and the friction coefficient of PTFE, and has nothing to do with the size of the support rotation angle. Therefore, it is especially suitable for the requirements of large corners, and the design corner can reach more than 0.06rad;


3. The rotation performance of the support is consistent in all directions, suitable for wide bridges, curved bridges, ramp bridges, inclined bridges and long-span bridges;


4. The spherical steel bearing does not need rubber to bear pressure, and there is no influence of rubber aging on the rotation performance of the bearing, especially suitable for low temperature areas.


Five, the technical performance of the support


1. Support reaction force (vertical bearing capacity) is divided into 21 levels: 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 6000, 7000, 8000, 9000, 10000, 12500, 15000, 17500, 20000 , 22500, 25000, 27500 and 30000kN.


2. The designed rotation angle of the support is 0.01 to 0.06rad.


3. Design displacement of support:


Moving bearing along the bridge: e=±50, ±100, ±150, ±200 and ±250mm


Two-way movable bearing cross-bridge direction: e´=±40mm


The displacement can also be adjusted according to the actual needs of the bridge.


4. Design friction factor of movable support


Under the vertical design load of the support, the design friction coefficient of the polytetrafluoroethylene plate under the condition of silicone grease lubrication is as follows:


Normal temperature (-25℃~+60℃): u=0.03


Low temperature (-40℃~-25℃): u=0.05


5. The applicable temperature range of the support is -40℃~+60℃.


6. The horizontal force that the support can bear:


The horizontal force borne by the fixed bearing and the one-way movable bearing in the constrained direction is 10% of the vertical design load of the bearing.


Six, the main material performance indicators


1. The polytetrafluoroethylene board should be molded with fresh pure materials. The raw material is SFB-2, and its main mechanical performance indicators meet the relevant regulations of GB/T 17955-2000 "Technical Conditions for Spherical Steel Bearings". The average particle size of PTFE raw materials shall not be greater than 50 μm, and the molding pressure shall not be less than 30 MPa. Its physical and mechanical properties are shown in the table below:


项   目试验标准性能要
GJB 30262140~2200kg/m3
拉伸强度GJB 3026≥29MPa
断裂伸长GJB 3026≥300%



2. The stainless steel plate used for the support is 1Cr18Ni9Ti finish rolling or mirror plate, and its chemical composition and mechanical properties shall comply with the relevant regulations of GB/T 3280-92. The grade of steel plate surface processing should meet the requirements of No.4 polishing and finishing surface group. The roughness Ra of the surface treatment of the stainless steel plate shall not exceed 1 μm, and the surface hardness shall be HV150~HV220.


3. The sliding surface of the support is made of 5201-2 silicone grease, its performance should remain unchanged within the range of temperature changes in the area where the support is used, it is harmless to all parts of the support, and has good ozone resistance, corrosion resistance and waterproof performance . Its technical performance indicators should comply with the relevant regulations of HG/T 2502-93.


4. The chemical composition, mechanical properties and impact toughness of steel castings after heat treatment comply with the relevant provisions of GB/T 11352-89. Steel castings shall be inspected one by one by ultrasonic flaw detection, and the detection method and quality rating method shall be implemented in accordance with the relevant provisions of GB/T 7233-87, and the castings shall reach Class I.


5. Q235B is selected as carbon structural steel, and its chemical composition and mechanical properties meet the relevant regulations of GB/T 700-88.


6. The high-quality carbon structural steel is 45#, and its chemical composition and mechanical properties meet the relevant regulations of GB/T 699-88.


7. The convex spherical surface of the spherical plate is plated with hard chrome, and the thickness is not less than 100μm. The base steel for hard chromium shall not have surface pores, shrinkage cracks and scars, and the chrome plating layer shall meet the conventional coating requirements of GB/T 11379-1989. After chrome plating, the surface must be polished, and the surface roughness Ra after treatment must not exceed 1.6μm.


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