Why use rubber mountings & how to select rubber mounting types
Part 1: Core purposes of using rubber mountings (anti-vibration rubber mounts)
Rubber mountings (elastomeric vibration isolators) are widely fitted for machinery, engines, pumps, fans, compressors and vehicle components mainly for 5 key reasons:
1. Vibration isolation (primary function)
Rubber’s inherent elastic and damping properties block the transmission of vibration:
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Stop vibration generated by running equipment transferring to building floors, frames or adjacent connected components;
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Isolate external ground vibration from disturbing precision instruments or sensitive machinery.
2. Noise reduction
Mechanical vibration is the main source of structure-borne noise. By cutting vibration propagation via rubber elasticity, structure-borne noise from equipment running is greatly lowered, improving working environment and meeting noise control standards.
3. Shock absorption & impact buffering
Rubber deforms elastically under sudden impact load to absorb instantaneous shock energy, protecting equipment parts from damage caused by startup shock, sudden load fluctuation or external collision.
4. Compensation for installation tolerance & thermal displacement
Machinery produces small thermal expansion/contraction from temperature change, plus minor assembly alignment errors during installation. Rubber’s flexible deformation offsets dimensional shift to avoid extra mechanical stress on equipment and fixing bolts.
5. Wear protection & service life extension
Eliminate rigid metal-to-metal contact friction and collision between equipment and base, reduce component fatigue wear, prolong service life of machines, bearings and connecting fittings.
2.Classify mount types by load direction:
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Mount type
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Load feature
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Application scenario
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Compression type rubber mount
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Mainly bear vertical compressive load
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Pumps, fans, small motors, ground-mounted equipment
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Shear type rubber mount
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Mainly bear horizontal shear load + minor vertical load
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Vehicle engines, suspended fans, floating mounting units
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Combined compression-shear mount
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Bear both vertical compression and horizontal shear
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Compressors, gensets with complex multi-direction vibration
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Annular/bushing rubber mount
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Radial load + small axial load
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Pipe hangers, shaft fittings, small oscillating parts
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3. Working environment conditions (determine rubber material grade)
Different rubber formulations adapt to different ambient conditions:
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Natural rubber (NR): Excellent elasticity & damping, good for normal room temp, dry air; avoid oil, high temperature; general-purpose indoor machinery.
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Nitrile rubber (NBR): Oil-resistant; use for engine, hydraulic pump near lubricating oil/fuel.
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EPDM rubber: Excellent weather/ozone/heat resistance; outdoor equipment, HVAC units exposed to sunlight and rain.
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Neoprene (CR): Balanced oil & weather resistance, moderate flame retardance; industrial outdoor compressors.
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Special harsh conditions (high temp >80℃, strong chemical corrosion, low temperature below -20℃): custom fluororubber (FKM) mounts.
5. Space constraint & installation way
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Limited installation height: thin disc-type compression mounts;
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Limited lateral space: cylindrical or bushing-type mounts;
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Bolt-through fixed installation: choose mounts with embedded metal inner/outer sleeves;
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Screw-top mounting for easy equipment fixing: captive bolt rubber isolators.
6. Special additional requirements
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Precision measuring instruments: high-damping low-stiffness mounts for ultra-low vibration transfer;
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Mobile/transport equipment: anti-roll combined rubber mounts with limit structure to prevent excessive displacement under tilt or shock;
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Fireproof industry: flame-retardant modified rubber mountings.
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4.Common typical rubber mount styles summary
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