After V-ring seals have been in use for a period of time, their lips will wear out. To ensure long-lasting sealing performance, it is necessary to promptly adjust their compression force. Therefore, the method for adjusting the compression force of V-rings must be considered during the design phase. Generally, the adjustment shim method is adopted: once the thickness and quantity of shims are specified, the adjustment amount can be controlled accurately. Adjustment can also be performed using nuts or springs:

• For seals with a diameter of less than 60mm, conical springs should be used;

• For seals with a diameter of more than 60mm, multiple small springs should be used for adjustment. The number of springs should be more than 3 and evenly distributed.

  If the adjustment method of "adjusting nut + spring" is adopted, the spring and the installation cavity of the V-ring seal must have good fitting accuracy and coaxiality.

1. Installation of V-Ring Seals

The inlet of the V-ring installation position should be chamfered or rounded to facilitate the installation of the seal. It can also be designed into a stepped shape: during installation, a guide sleeve can be inserted to make the seal easier to fit into place.

2. VD-Type Rubber Seals

A VD-type rubber seal is formed by thickening one side of the lip of a standard V-ring seal. It is suitable for dynamic sealing of rotating shafts (with a shaft circumferential speed not exceeding 19m/s) and can also be used as face seals and dust seals.

3. Type and Dimension of VD-Type Rubber Seals

VD-type rubber seals are classified into Type S and Type A. Their dimensions can be referenced in the standard JB/T 6994—1993 (China Machinery Industry Standard).

4. Material and Surface Roughness Requirements for VD-Type Rubber Seals

Material: Nitrile Butadiene Rubber (NBR) or Fluororubber (FPM).

Surface Roughness:

• The surface roughness of the seal itself should be Ra 3.2μm;

• The surface roughness of the metal parts in contact with the seal lip should be Ra 1.6μm.