250*7 / 255.5.5 rear wheel rubber o ring seals NBR rubber o ring cord for ND

Size & Styles 

 1.Inside and outside packing is listed as below for your selection or Plain packing as your request

2.FOB QINGDAO or others ports as nornimated

3.Express /Air /SEA shipment is acceptable  

 Factory  View -Actual Photos

Factory Inspection Machine & Process

Factory Self Inspection report  : 

3rd Party Inspection requested by customer

Copy right packing design and Registered self-own Brand

Existing Customer

What is O ring  ? 

An O ring is a torus or doughnut shaped ring , generally molded from an elastomer ,although O rings are also made from PTFE and other material , both are hollow and solid .

O rings are used primarily for sealing with various of types , and also for light-duty ,mechanical drive belts .

Sealing Principle :  

The rubber seal should be considered as essentially an incompressible , viscous fluid having a very high surface tension . Whether-by mechanical pressure from the surrounding structure or by pressure transmitted through hydraulic fluid ,the extremely viscous fluid is forced to flow within the gland to produce “ zero clearance “ or block to the flow of the less viscous fluid being sealed .

The rubber absorbs the stack-up of the tolerance of the unit and its internal memory maintains the sealed condition.

Below pictures is showing how it works .

Material Selection

Nitrile Rubber ( NBR )

   NBR is most commonly used material. It has good heat resistance properties, good resistance to oils, salt solutions, hydraulic oils, and gasoline. Operation temperatures are recommended from -40° to 120°C. It also functions well under dry environment, but only for intermittent periods. The disadvantage is poor chemical resistance.

Polyacrylate Rubber (PA)

   Acrylic rubber has better heat resistance than Nitrile. It is recommended for high surface speed environment. The operation temperatures are recommended from -20° to 150°C. It should not be used with water or in temperature below -20°C.

Silicone Rubber (SI)

   Silicone compounds operate effectively in a broad temperature range of -50° to 180°C. It is unsurpassed in its resistance to heat and low temperatures. The high lubricant absorbency of silicone minimizes friction and wear. It is usually used for crank shaft seals. Silicone has poor hydrolysis resistance. It should not be used in oxidized or hypoid oils.

Fluorinated Rubber (VI)

   Fluorinated rubber is widely known under the du Pont trade name of Viton R. It has the best resistance to chemicals, and superior performance to high temperatures. Though VITON provides so many good prospects, it has the highest cost.

Performance of Hualei Seals  

O Ring Application