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Piston Seal K01–K07・K21 (Lip Type, Compact Seal)

K01-K21 / SKF (Official website)

A group of lip-type (U-cup) piston seals with standard housing dimensions matched to cylinder bore and groove diameters.

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How to choose Piston Seals

Points to check when selecting, with the values for this product (Piston Seal K01–K07・K21 (Lip Type, Compact Seal)).

  1. 1. Match cylinder bore and groove dimensions

    The seal is designed around the combination of cylinder bore D, piston-side groove diameter d, and groove width L. If these three dimensions do not match, excess or insufficient squeeze (the amount by which the seal is compressed) causes leakage, premature wear, or improper installation. When replacing parts on existing equipment, measure the groove and check whether a matching dimensional series is available.

  2. 2. Choose single-acting or double-acting by application

    Use single-acting types for cylinders pressurized on one side only, and double-acting types for double-acting cylinders pressurized in both directions. Single-acting types often have asymmetric cross-sections, and sealing fails if they are installed in the wrong orientation. Double-acting types generally have symmetric cross-sections and seal pressure in both directions with a single seal.

  3. 3. Allow margin for maximum pressure

    The listed products have maximum pressures ranging from 25 to 1500 bar. Compare them using the maximum pressure including surge pressure (momentary pressure spikes). At high pressure, extrusion into the clearance gap is more likely, so backup-ring-integrated designs or high-pressure-rated profiles are good candidates.

  4. 4. Select material by fluid and temperature

    Polyurethane-based materials offer excellent wear resistance and pressure resistance and are widely used in hydraulics. PTFE-based materials have low friction and high chemical and heat resistance, making them suitable for chemical and food applications. Rubber-based materials such as NBR are common materials for mineral oil applications. Select a material compatible with the working fluid and temperature range (listed products include examples from -60 to 260°C).

  5. 5. Check sliding speed and friction characteristics

    The listed products have maximum sliding speeds of 0.3 to 15 m/s. High-speed operation and frequent reciprocating motion increase heat generation and wear. In low-speed positioning, stick-slip (vibration caused by sticking) becomes a concern, so profiles with PTFE-based slide rings, which have low breakaway resistance, are suitable.

  6. 6. Consider integrating guide functions

    Profiles that incorporate guide ring functions allow a shorter piston length and reduce the number of components. However, when lateral loads are high, designs that combine a separate guide ring are common. Select the profile after reviewing the groove configuration and lateral load conditions.

This guide was written by AI based on the listed products' documents and specification items.

About Piston Seals and all products

Description

Offers high stability within the housing and excellent sealing performance over a wide temperature range. Materials include ECOPUR, SKF Ecorubber, and others.

Features

  • U-cup profile
  • Sealing over a wide temperature range

Applications

  • Support and retention cylinders
  • Standard cylinders

FAQ

Q. What applications can the Piston Seal K01–K07・K21 (Lip Type, Compact Seal) be used for?
A. They can be used for support and retention cylinders and standard cylinders.
Q. What are the profile and sealing performance of the Piston Seal K01–K07・K21?
A. It is a lip type with a U-cup profile. It has high stability within the housing and excellent sealing performance over a wide temperature range.
Q. What materials are available for the Piston Seal K01–K21?
A. Materials include ECOPUR, SKF Ecorubber, and others.
Q. Can the Piston Seal K01–K07・K21 be selected according to cylinder bore and groove diameter?
A. It is a seal group with standard housing dimensions matched to cylinder bore and groove diameters.

Written by AI based on the content of the source documents.

Source documents

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