Bearing Seals Guide

Function

Bearing is a commonly used mechanical component. A good bearing needs to have excellent sealing performance during use, and the bearing sealing device plays an important role. It can not only effectively prevent external dust, moisture or other foreign matter from invading the bearing internally, thereby affecting bearing life; it can also prevent lubricant leakage.

• Protect bearings

Prevent external dust, dirt, metal particles, moisture, acid gas and other debris from intruding into the inside of the bearing. If the bearing seal is poor and external debris invades, the working condition of the bearing will significantly deteriorate, and the service life of the bearing will be significantly reduced.

• Prevent grease leakage

If oil leaks, it will quickly destroy the normal lubrication of the bearing and cause the bearing to burn out due to heat. In addition, poor sealing devices not only cause waste due to oil leakage, but also contaminate mechanical equipment and processed products. Therefore, for the machine to operate normally, the bearings must have good sealing devices.

Types

Bearing seals can be divided into two categories: self-contained seals and external seals.

Comes with seal

The so-called bearing comes with a sealing device, which means that the bearing itself is made into a device with sealing performance. Such as bearings with dust covers, sealing rings, etc. This kind of seal takes up very little space, is easy to install and disassemble, and has a relatively low cost.

Additional sealing

The so-called bearing external sealing performance device is a sealing device with various performances made inside the installation end cover. External seals are divided into two types: non-contact and contact:

• 1) Contact sealing

A contact seal is a seal that is in contact with its relatively moving parts without gaps. Due to the direct contact between the seal and the mating parts, this type of seal has greater friction and heat generation during operation, which can easily lead to poor lubrication and easy wear of the contact surface, resulting in a decrease in sealing effect and performance. Therefore, it is only suitable for medium and low speed working conditions. Commonly used contact seals include felt seals, cup seals and other structural forms, which are used in different occasions. The contact area between the shaft and seal needs to be lubricated, usually with the same lubricant as the bearing.

Contact sealing devices mainly include: Z-shaped sealing rings, V-shaped sealing rings, oil seals, etc.

• 2) Non-contact sealing

Non-contact seal Non-contact seal is a seal that does not contact the relative moving parts and has an appropriate gap. This form of seal generates almost no frictional heat and no wear during operation, and is especially suitable for high-speed and high-temperature applications. Non-contact seals are commonly used in various structural forms such as gap type, labyrinth type and gasket type, which are used in different occasions. The gap of the non-contact seal should be as small as possible.

Non-contact sealing devices mainly include: gap seal, oil groove seal, labyrinth seal, oil slinger, etc.

Hybrid seal

In harsh environments such as dust and moisture, and in situations where lubricant leakage is not allowed, various sealing forms are often used in combination to achieve better sealing effects.

Codes for different types of bearing seals