Joints d'arbre rotatif

About Rotary Shaft Seals

Rotating shaft seals, also called gland seals and shaft sealing rings, are often used to solve dynamic sealing problems. Rotary shaft seals are elastomer seals with a rubber housing surrounding a spring. The cylindrical housing provides a static seal and ensures that the seal is locked inside its housing.

Material Composition of Rotary Shaft Seals

Rotary shaft seals are primarily composed of two key materials: flexible elastomers and supporting metal frames. This combination optimizes the seal’s ability to maintain a safety barrier while accommodating the dynamic movement of the rotating shaft.

1. Elastomer material
The main sealing element of Rotary shaft seals is a flexible lip that is in direct contact with the shaft. The lip is usually made of an elastomeric material, the more common rubber being NBR or FKM. The choice of elastomer depends on the specific application, operating conditions and the fluids the seal will encounter.

NBR is widely used in rotary shaft seals due to its excellent oil resistance and cost-effectiveness. It provides reliable sealing for applications involving lubricants, fuels and non-corrosive fluids.

FKM seals offer superior resistance to a wider range of chemicals, including corrosive liquids, fuels and high temperature environments. FKM seals are suitable for applications where extreme conditions or exposure to corrosive substances are expected.

2.Metal frame:
Supporting the elastomeric lip is a metal frame that provides structural integrity and stability to rotary shaft seals. Metal frames are usually made of stainless steel or other corrosion-resistant metals. The frame strengthens the seal, prevents deformation, and maintains proper pressure on the rotating shaft, ensuring an effective seal.

The material composition of rotary shaft seals involves a subtle balance between elastic properties and structural support. The harmonious combination of NBR and FKM with a carefully selected metal frame effectively seals the rotating shaft while maintaining durability and resistance to various operating conditions. The selection of these materials is guided by the specific requirements of each application, ensuring rotary shaft seals perform their important sealing role reliably and efficiently.

Functions of Rotary shaft seals

Rotary shaft seals, also called radial shaft seals, have two main functions:

1. Fluid sealing: The main purpose of Rotary shaft seals is to contain fluid within the system. Whether it’s lubricating oil, hydraulic oil, or other types of fluids, seals ensure they stay within their designated space and don’t leak. This function is critical to maintaining the proper operation and efficiency of various mechanical systems.

2. Contaminant exclusion: In addition to fluid sealing, Rotary shaft seals can also prevent the entry of contaminants, such as dirt, dust, moisture and other harmful particles. By creating a barrier between internal systems and the external environment, seals protect rotating shafts and other critical components from potential damage, wear and corrosion.

Structure of rotary shaft seals

Typical rotary shaft seal consist of several key components:

1. Metal shell: The metal shell provides structural support and rigidity for the seal. It also helps to secure the seal within the housing or hole.

2. Elastic lip: The elastic lip is the dynamic sealing element of the seal. It contacts the rotating shaft and forms a tight seal to prevent fluid leakage. Lips are typically made from materials such as rubber or synthetic elastomers, chosen for their durability, flexibility and resistance to a variety of operating conditions.

3. Clamping spring: In some rotary shaft seal, a clamping spring is installed to exert radial pressure on the lip to ensure consistent contact with the shaft surface. The spring helps maintain the sealing effect during shaft movement and ensures a safe seal under different operating conditions.

Applications

Rotary shaft seals are used in a wide range of industries and machinery, including food, automotive, aerospace, manufacturing, power generation, and more. They are used in engines, pumps, gearboxes, electric motors and any equipment that needs to seal fluids and prevent contamination along the rotating axis.