Release time : 2015-06-10 07:04:30
For miniature ball bearings
which have exactly the same design as deep groove ball bearings that contents inner race, outer race, cage, balls and closures. Even for smallest ball bearing, we could provide them with metal shields.
Here are some introductions of how to express closures in bearing code.Usually we will add following suffix in bearing fields such as 693ZZ or 693 2RS and so on:
RS means only one rubber seal on one side (do not matter which side)
Z means only one metal shield on one side (do not matter which side)
2RS means two rubber seals on both sides
ZZ means closed with metal shields
Open style means there is no any rubber seals or metal shields on both side.
Most sizes are available with metal shields. Shields are designed to prevent larger particles from entering the ball bearing and also to keep grease inside the bearing.
Metal shields have following properties
1) Prevent contamination by larger particles
2) Reduce lubricant leakage
3) Do not increase torque
Contact Seals (2RS)
The standard miniature ball bearing seals are made in BUNA-N rubber. But we also have some high temperature seals such as Teflon or Viton. High temperature teflon seals (up to 250?centigrade?degree) or Viton seals (up to 230?centigrade?degree) are available on some sizes.?Seals can prevent smaller particles such as dust and moisture enter into bearing while preventing lubricant leakage. Contact seals produce much higher frictional torque levels than shields and reduce the maximum speed of a bearing.
Seals have following properties:
1) Good protection against contamination
2) Greatly reduce lubricant leakage
3) Reduce maximum speed by approx. 40%
4) Temp. range -40?centigrade?degree/+110?centigrade?degree?(nitrile rubber) or up to 230?centigrade?degree(Viton) and 250?centigrade?degree(Teflon)