How is the structural design of the JQZ series ball bearings
The JQZ series spherical bearings are the core load-bearing components that are suitable for large-span spatial structures such as bridges, sports halls, and high-speed railway stations in construction engineering. Their structural design revolves around four core requirements: "multi angle rotation, bidirectional displacement compensation, high-strength bearing, and long-term durability". They ad
The JQZ series spherical bearings are the core load-bearing components that are suitable for large-span spatial structures such as bridges, sports halls, and high-speed railway stations in construction engineering. Their structural design revolves around four core requirements: "multi angle rotation, bidirectional displacement compensation, high-strength bearing, and long-term durability". They adopt modular combination design and can adapt to different spans, loads, and displacement conditions. The following provides a detailed analysis of the core structure composition, design highlights, key technical parameters, and adaptation scenarios:
1、 Core highlights of structural design (adapted to engineering requirements)
1. Rotating mechanism design: Multi angle flexible rotation, adaptable to structural deformation
Ball joint contact design: The middle ball core adopts a "spherical contact" structure (the spherical curvature radius R of the crown liner plate is usually 1.5-2.5 times the diameter of the support), which can achieve rotation in any direction from ± 5 ° to ± 10 ° (the specific angle depends on the support model, and the support angle for large-span bridges can reach ± 15 °), suitable for scenarios such as beam deflection deformation and structural temperature stress release (such as end rotation caused by bridge mid span deflection).
Optimization of rotational friction: A modified PTFE sliding plate (friction coefficient μ ≤ 0.03) is embedded on the contact surface between the ball crown liner plate and the upper/lower support plate, combined with a stainless steel sliding surface, to achieve low friction loss during rotation, avoid jamming, reduce component wear, and extend service life.
2. Displacement compensation design: bidirectional/unidirectional displacement adaptation to meet the needs of multiple scenarios
The JQZ series can be divided into three types through different guiding structure designs: fixed type (JQZ-GD), unidirectional displacement type (JQZ-DX), and bidirectional displacement type (JQZ-SX), which are suitable for different displacement requirements:
Fixed type: The upper and lower support plates are locked by limit blocks, allowing only rotation and not horizontal displacement (suitable for scenarios where there is no displacement at the end of the structure, such as the fixed end of a continuous beam bridge);
Unidirectional displacement type: The upper support plate is equipped with longitudinal/transverse guide grooves to limit displacement perpendicular to the guide direction, allowing only horizontal displacement in a single direction (displacement of ± 50mm~± 200mm, suitable for longitudinal expansion and contraction scenarios of bridges);
Bidirectional displacement type: without directional restrictions, allowing for arbitrary bidirectional displacement in the horizontal direction (displacement of ± 50mm~± 300mm, suitable for the multi-directional displacement requirements of large-span spatial structures (such as sports hall roofs).
Displacement buffering design: The PTFE skateboard adopts a "convex groove" embedded fixing method to prevent the skateboard from falling off during displacement; Partial large displacement supports are equipped with stainless steel sliding plate extension layers to ensure continuous sliding surfaces throughout the displacement process and improve stability.
3. Load bearing structure design: high strength, impact resistance, suitable for heavy-duty working conditions
Main material reinforcement: The upper and lower support plates and ball cores are made of high-strength structural steel (Q355B/Q460C), which is welded and subjected to overall heat treatment (to eliminate welding stress) to ensure the overall bearing capacity of the support (rated vertical bearing capacity can reach 100kN~50000kN, covering the requirements of medium to large-span engineering).
Stress dispersion design: The spherical surface of the crown liner adopts a uniform stress design, which disperses the concentrated load from the upper part to the lower support plate, avoiding local stress concentration (contact stress ≤ 250MPa); The bottom of the lower support plate adopts a thickened design (thickness ≥ 30mm) and is equipped with stiffeners to enhance the stability of the connection with the foundation and prevent the support from sinking.
Anti pull/anti horizontal force design: For earthquake, strong wind and other working conditions, some JQZ supports are equipped with anti pull devices (such as anti pull anchor bolts, limit pins), and the anti pull bearing capacity can reach 30%~50% of the vertical bearing capacity; The horizontal bearing capacity can reach 20% to 30% of the vertical bearing capacity, effectively resisting the impact of horizontal loads (such as transverse wind loads on bridges and seismic horizontal forces).
4. Anti corrosion and dustproof design: Long term durability, suitable for harsh environments
Multiple anti-corrosion coatings: After sandblasting and rust removal (Sa2.5 level) on the surface of the main steel structure, apply epoxy zinc rich primer (thickness ≥ 80 μ m) and polyurethane topcoat (thickness ≥ 60 μ m). In outdoor scenarios, an additional fluorocarbon coating can be added, with a salt spray corrosion resistance time of ≥ 5000 hours, suitable for humid/corrosive environments such as bridges and seaside buildings.
Sealed dustproof design: A chloroprene rubber dust cover (or stainless steel dust ring) is installed between the upper and lower support plates, completely covering the internal ball core and sliding surface, preventing dust, rainwater, and debris from entering, and avoiding PTFE sliding plate wear and steel structure corrosion.
Slip surface protection: The stainless steel slip surface is made of 304/316L stainless steel, with surface polishing treatment (roughness Ra ≤ 0.8 μ m) to enhance wear resistance and corrosion resistance; PTFE skateboards are reinforced with carbon fiber, copper powder, and other additives to improve their high temperature resistance (-40 ℃~+80 ℃) and wear resistance, with a service life of ≥ 50 years (design service life).
5. Installation and maintenance design: convenient and easy to maintain
Modular installation: The various components of the support are connected by bolts, and there is no need for on-site welding during installation. Only the lower support plate is fixed to the foundation embedded steel plate through anchor bolts, and the upper support plate is welded/bolted to the reserved steel plate of the upper structure, resulting in high construction efficiency.
Leveling design: Leveling bolt holes are reserved at the bottom of the lower support plate, which can be used to adjust the levelness of the support (levelness deviation ≤ 0.5 ‰) to ensure even force distribution on the support.
Convenience of maintenance: The dust cover adopts a detachable design, which facilitates regular inspection of the wear of the internal sliding surface and ball core; The PTFE skateboard can be replaced separately without the need to remove the support as a whole, reducing maintenance costs.
3、 Key design parameters (industry standard adaptation)
The structural design of JQZ series spherical bearings strictly follows the "Technical Conditions for Spherical Bearings" (GB/T 17955-2019), and the core design parameters are as follows:
1. Vertical bearing capacity: 100kN~50000kN (selected according to engineering requirements);
2. Angle range: ± 5 °~± 15 ° (small tonnage support angle can reach ± 20 °);
3. Horizontal displacement: unidirectional ± 50mm~± 200mm, bidirectional ± 50mm~± 300mm (larger displacement can be customized);
4. Friction coefficient: At room temperature (23 ℃), the friction coefficient between PTFE sliding plate and stainless steel sliding surface is μ ≤ 0.03;
5. Applicable temperature range: -40 ℃~+80 ℃ (low-temperature resistant PTFE skateboard can be selected for low-temperature scenarios, suitable for -60 ℃ environment);
6. Anti corrosion grade: ≥ C5 grade (compliant with ISO 12944 standard), suitable for outdoor, seaside, and industrial corrosive environments;
7. Design service life: ≥ 50 years (fatigue life of main steel structure ≥ 2 million times).
4、 Adaptability between structural design and application scenarios
The structural design of the JQZ series is targeted to meet the core requirements of different engineering scenarios, with typical adaptation scenarios as follows:
1. Bridge engineering (highway/railway bridge):
Long span continuous beam bridges and cable-stayed bridges: using bidirectional/unidirectional displacement type JQZ supports, adapting to beam deflection deformation through ball joint rotation, compensating for temperature expansion and contraction with horizontal displacement, and resisting horizontal seismic forces with anti pull devices;
High speed railway bridge: High stiffness and low friction coefficient bearings (μ ≤ 0.02) are selected to ensure stability during train operation, with angle accuracy controlled within ± 0.5 ° to reduce beam vibration.
2. Large span spatial structures (sports halls, high-speed railway stations):
Roof steel structure (such as grid and shell): Adopting bidirectional displacement type JQZ supports, it adapts to the multi-directional displacement and rotation of the roof structure caused by temperature changes and load effects, avoiding structural stress concentration;
Curtain wall support: Use small tonnage JQZ supports (100kN~500kN) to achieve slight rotation and displacement of the curtain wall panels, absorb wind loads and temperature deformation, and prevent curtain wall cracking.
3. Industrial buildings (factory buildings, equipment foundations):
Heavy equipment foundations (such as boilers and generators): Fixed JQZ supports are used to provide high-strength load-bearing capacity, limit equipment displacement, and absorb vibration during equipment operation through ball joint rotation, reducing impact on the foundation.
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