Views: 3 Author: Site Editor Publish Time: 2023-10-27 Origin: Site
Rubber damping products are generally referred to as rubber dampers. There are many types of rubber dampers, and they can be categorized based on the type of vibration force they endure, such as compression, shear, torsion, impact, and hybrid types. With the advancement of technology, the types of rubber dampers are increasing, and their applications are becoming more diverse. Below is an overview of the development and application prospects of rubber dampers in various fields.
Rubber Damping Products for Railway Locomotives and Rail Sleeper Pads
In China, various rubber materials and components used in railways and locomotives number over 10,000 types, consuming approximately 10,000 tons of rubber annually. As the speed of railway locomotives increases, the demand for vibration resistance in various parts of locomotives, such as central bearing rubber stack, axle box pull rod rubber spring, side bearing rubber stack, motor suspension rubber pad, elastic wheels, elastic gears, rubber air springs, and rubber ball joints in the transmission device, has increased. Rubber damping products used in locomotives primarily bear compressive stress, shear stress, and torsional moments and often need to withstand the combined action of two or more stress types simultaneously.
With the rapid development of China's railway construction, concrete sleepers have replaced wooden sleepers. Although concrete sleepers have a longer service life and improved stability of track framework structures, they reduce the elasticity of the track, leading to a decline in cushioning properties against wheel-rail impacts. To enhance the cushioning performance of concrete sleepers, reduce the impact force on sleepers, and improve insulation, elastic polymers are used to address the elasticity issue of concrete sleeper tracks. Rubber sleeper pads are used between steel rails and concrete sleepers or under the sleepers, and they are widely used in railway lines due to their unique elasticity and excellent insulation properties.
Depending on their use, rubber sleeper pads are generally classified into two types: above the sleeper (below the rail) pads and below the sleeper pads. These rubber sleeper pads must exhibit good resistance to natural aging, heat, cold, as well as excellent elasticity, cushioning, and shock-absorbing properties. They should also have good wear resistance, electrical insulation, compression resistance, and shear resistance. Common main materials include NR, SBR, BR, CR, and EPDM.
Rubber Damping Products for Construction Engineering
Construction of earthquake-resistant buildings and structures is an essential topic in the field of construction engineering due to natural disasters like earthquakes. Increasing traffic density leads to greater vibration transmission and noise pollution, making isolation of vibrations and noise in civil engineering structures a crucial issue.
Since the late 1960s, rubber base isolators have been widely used for seismic isolation in various construction projects. In recent years, a broad range of structures, including bridges, buildings, and water structures, use base isolators to improve their earthquake resistance. The use of laminated rubber bearings in construction engineering has proven to be highly effective. These isolators not only find applications in bridge construction but are also used in the foundations of buildings, providing earthquake protection. Rubber base isolators have been extensively used in both line structures such as roads, railways, and subways, as well as water structures.
Rubber Damping Products for Automobiles
The automotive industry is going through rapid changes with frequent model updates and replacements of vehicles. The focus is on improving vehicle longevity while ensuring driving safety, comfort, high-speed performance, and luxury. Damping products are used to control vehicle vibrations and noise and improve its handling stability. They are typically placed in various parts of the vehicle, such as the engine mount, control arms, suspension bushings, center bearing brackets, bump stops, and torsional dampers, to enhance safety and comfort. Damping products are categorized into support, bushing, cushion, and damper types, with requirements for good damping performance, heat resistance, and fatigue resistance.
Rubber damping products for automobiles include engine mounts, suspension components, rubber springs, rubber air springs, and impact rubber protective parts. In recent years, the variety and quantity of rubber damping products used in automobiles have increased, with a single car having 50-60 rubber damping products.
Rubber Damping Products for Bridges
In bridge engineering, bearings are used at both ends of a girder to transfer all loads (including dead and live loads) reliably to the piers and to accommodate horizontal displacements and rotations caused by the loads. Bearings are classified as fixed and expansion bearings. Fixed bearings hold the girders in a fixed position, allowing rotation but no translation. Expansion bearings, on the other hand, not only allow rotation but also permit translation, accommodating movements due to temperature changes, concrete shrinkage, and load-related factors.
Rubber bridge bearings have been widely used in bridge engineering. These bearings are favored for their reliable performance, simplicity in design, easy manufacturing, and the availability of materials. They can adapt to the deformation of superstructures in various directions, making them suitable for both small and large span bridges. Currently, three common types of rubber bridge bearings are widely used: plain rubber bearings, PTFE (polytetrafluoroethylene) sliding bearings, and box-type rubber bearings.
Rubber bridge bearings are made from natural rubber, chloroprene rubber (CR), EPDM rubber, isobutylene-isoprene rubber (IIR), and chlorinated IIR. The choice of rubber material depends on performance requirements and environmental conditions. Rubber bridge bearings are typically manufactured through compression molding. The production process involves compounding rubber with appropriate additives to create a blend, which is then molded into semi-finished rubber sheets. These sheets are cut into specific dimensions before being cured in a vulcanizing press. Care must be taken to ensure uniform thickness and prevent movement of the steel plates during curing.
In bridge engineering, lead core rubber bearings are commonly used. These bearings involve embedding lead within the rubber to increase energy absorption and provide adequate damping. They are effective in controlling wind response and resisting micro-vibrations from the foundation.
High-damping rubber bearings are made using high-damping rubber materials. These materials can be prepared by incorporating graphite into natural rubber or synthetic rubber. The damping characteristics of high-damping rubber can be adjusted by varying the graphite content. Like lead core rubber bearings, high-damping rubber bearings serve both as isolators and dampers, making them suitable for independent use in isolation systems.
Damping Product Categories:
These are rubber products specifically designed for damping and cushioning. They are typically made from natural rubber, chloroprene rubber (CR), EPDM, isobutylene-isoprene rubber (IIR), and chlorinated IIR, depending on the requirements. Some products may require nitrile rubber (NBR) for oil resistance, silicone rubber (VMQ) for high and low-temperature resistance, and butyl rubber (IIR) for high damping properties. Damping products are commonly used as support or connecting components in various vehicles, ships, machinery, instruments, bridges, buildings, and other applications to mitigate the adverse effects of vibrations.
Two Key Parameters for Damping Products:
Static Stiffness: It represents the ratio of the change in pressure (or tension) to the change in displacement of the rubber damper within a certain displacement range. The measurement of static stiffness must be performed within a specific displacement range, and different displacement ranges may yield different static stiffness values. Some customers may require the entire displacement range to be measured.
Dynamic Stiffness: It represents the ratio of the change in pressure (or tension) to the change in displacement of the rubber damper within a certain displacement range and at a specific frequency. Dynamic stiffness measurement is typically performed within a defined displacement range and at specific frequencies, and different displacement ranges and frequencies may yield different dynamic stiffness values.
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