Core Material Selection for Jack Buffer and Shock-Absorbing Rubber Blocks
Jack buffer and shock-absorbing rubber blocks are key components used to reduce impact loads, absorb vibration, and improve stability during lifting operations. The selection of the core rubber material directly affects load capacity, damping performance, durability, and operational safety. A rational material choice should be based on mechanical requirements, working environment, and service life expectations.
1. Performance Requirements for Core Materials
The core material of a jack rubber block must meet several fundamental performance criteria. It should have sufficient compressive strength to withstand high static and dynamic loads without permanent deformation. Good elasticity and resilience are required to absorb impact energy and recover quickly after unloading. A low compression set is essential to maintain thickness and buffering capability during long-term use. In addition, the material should provide an adequate friction coefficient to prevent slippage and exhibit resistance to aging, temperature variation, moisture, and oils, depending on the application environment.
2. Commonly Used Core Rubber Materials
Natural rubber is widely used for general jack buffer applications due to its excellent elasticity, high resilience, and superior shock-absorbing performance. It performs well under moderate loads and normal temperature conditions. However, its resistance to oil, ozone, and high temperatures is limited, making it less suitable for harsh environments.
Styrene-butadiene rubber is commonly selected for its balanced mechanical strength, abrasion resistance, and cost efficiency. It offers stable performance in indoor or standard industrial environments where oil and chemical exposure are minimal. Its aging resistance is moderate compared with specialized elastomers.
Nitrile butadiene rubber is preferred in applications where contact with oil, grease, or fuel is unavoidable. It provides good oil resistance and satisfactory compressive properties, making it suitable for automotive jacks and industrial maintenance equipment. Its elasticity is slightly lower than that of natural rubber but sufficient for buffering purposes.
Ethylene propylene diene monomer rubber is characterized by excellent resistance to heat, ozone, weathering, and UV radiation. It is particularly suitable for outdoor jacks or equipment exposed to sunlight and temperature fluctuations. However, its oil resistance is relatively poor, which limits its use in oily environments.
Polyurethane elastomer is used for heavy-duty jack buffer blocks requiring high load-bearing capacity and wear resistance. It exhibits low compression set and long service life under repeated loading. Although its damping performance is generally lower than that of softer rubbers, its mechanical strength makes it ideal for high-load and high-frequency applications.
3. Hardness and Structural Considerations
Rubber hardness is typically selected in the range of Shore A 60 to 90, depending on load and vibration requirements. Softer materials provide better shock absorption but may suffer from excessive deformation, while harder materials offer higher stability and load capacity at the expense of damping efficiency. In some designs, layered or composite structures are adopted to achieve an optimal balance between cushioning and structural support.
Conclusion
The core material selection for jack buffer and shock-absorbing rubber blocks should comprehensively consider load conditions, environmental exposure, durability requirements, and safety factors. Natural rubber and SBR are suitable for general applications, NBR is recommended for oily environments, EPDM is ideal for outdoor use, and polyurethane is best suited for heavy-load conditions. Proper material selection ensures reliable buffering performance, extended service life, and safe lifting operations.
References
Gent, A. N. Engineering with Rubber: How to Design Rubber Components. Hanser Publishers, 2012.
ASTM D2000 – Standard Classification System for Rubber Products in Automotive Applications.
Lake, G. J. “Fatigue and Fracture of Elastomers.” Rubber Chemistry and Technology, 2000.
ISO 7619-1 – Rubber, Vulcanized or Thermoplastic — Determination of Indentation Hardness.
