Reciprocating squeeze gaskets
Description
Introduction
Squeeze gaskets are available in a variety of dimensions and shapes. The squeeze gasket has the following characteristics: ① Reasonable price ② Small footprint ideal for miniaturized or simplified equipment ③ Self seal type usable in a wide range of pressure and temperature for a wide varieties of fluid and environment ④ Easy attachment and replacement, no need for adjustment ⑤ Ease of selection by the user
| Name | Sectional shape | Cost | Torsion | Frictional characteristics | Pressure resistance | Handling |
|---|---|---|---|---|---|---|
| O Rings |
|
○ | × | △ | △ | ○ |
| D rings |
 
|
○ | △ | × | △ | △ |
| X rings |
 
|
△ | ○ | ○ | × | △ |
| T rings |
|
× | ○ | ○ | ○ | × |
Characteristics of gaskets
O ring: Most common type of squeeze gaskets. ISO, JIS, JASO, and other standards are stipulated. This type can be easily designed and handled. O rings are available at low prices.
D ring: A D ring has a D-shaped cross section. A D ring for a reciprocating mechanism is less likely to twist than the O ring. The D ring is often utilized as measures against torsion of the O ring. In recent years, many D rings have been used for reciprocating mechanisms such as automatic transmission (AT) of automobiles and brakes of construction machines.
X ring: An X ring having an X-shaped cross section is used as a gasket of reciprocating mechanisms and some rotating mechanisms. The X ring is used as measures against torsion of the O ring. The X ring also has excellent frictional characteristics and excellent sealing performance. Due to lack of rigidity, however, the X ring is not suitable for high-pressure applications.
T ring: A T ring having a T-shaped cross section is used as a seal of low frictional characteristics. The T ring has been recognized as a gasket for wide-range reciprocating mechanisms and low-speed crack-and-rocker mechanisms. In combination with a backup ring, the T ring has higher pressure resistance. The difficulty of assembly, however, makes it cost more than other squeeze gaskets.
Selecting a material
A material should be selected, depending on the conditions of use such as environment, temperature, fluid type, and pressure. Please do not hesitate to contact our sales office nearest to you. Refer to the summary of types of NOK O rings for securing seals or non-metallic squeeze gaskets and types and characteristics of NOK O ring materials.
Specifying seal dimensions and groove dimensions
Refer to the catalog of each product. For any special application, please contact our sales office nearest to you.
Groove roughness
The sliding surface of a gasket has a strong influence on the frictional characteristic and wear characteristics of the gasket. For a recommended value of surface roughness, see the surface roughness of the groove part of the securing seal or non-metallic squeeze gasket. A cross-hatched surface produced by honing is desired. A roughly corrugated surface with sharp peaks is not desired.
Groove clearance
The groove clearance should be minimized as far as possible. If the groove clearance exceeds a limit, it is recommended to use a backup ring. For the groove design and use of backup ring, contact our sales office nearest to you.