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Quick Answer: CORASEALS is a U-cup seal supplier for hydraulic cylinders, pneumatic cylinders, rod sealing, and piston sealing applications. We quote U-cup seals based on the seal profile, material, ID, OD, groove dimensions, pressure, speed, fluid, and operating temperature. Send us your drawing, sample photo, or measured dimensions for a U-cup seal quotation.
U-cup seals are lip-type seals with a U-shaped cross section. They are used mainly in reciprocating hydraulic and pneumatic cylinders. The U-cup design uses system pressure to press the sealing lips against the rod or bore and the groove sidewall. The U-cup design allows the seal to work in low and high pressure conditions when the seal profile and groove match correctly.
CORASEALS can quote U-cup seals based on your existing part number, sample, drawing, or measured dimensions. Common profile codes include UN, UHS, UPH, and DH, but these codes are not treated as automatic interchange signals. Different catalogs define these codes differently. CORASEALS confirms the lip geometry, cross section, ID, OD, groove width, and material before quoting.
Common U-cup seal materials include the following.
Material selection depends on the hydraulic fluid, temperature range, pressure cycle, and surface finish of the rod or bore. CORASEALS does not assign a fixed temperature or pressure rating without checking the material grade and groove design.
U-cup seal dimensions are usually stated as inside diameter, outside diameter, and groove width or seal height. Some customers provide rod diameter, bore diameter, and groove dimensions from the cylinder drawing. Others provide an existing part number, sample photo, or measured seal dimensions. Both methods are acceptable.
Dimensions can be given in millimeters or inches. CORASEALS works with both metric and inch U-cup seal sizes. Always state the unit next to each measurement.
To get accurate pricing, include these details.
Send us the rod diameter, bore diameter, groove dimensions, pressure, speed, hydraulic fluid, and seal profile. If you have a drawing or sample photo, include that with your inquiry.
U-cup seals are common in mobile and industrial hydraulic cylinders. Typical equipment includes excavators, loaders, agricultural machinery, forklifts, presses, lifting platforms, and pneumatic actuators. The seal position can be a rod seal or a piston seal. U-cup seals can also be used in some pneumatic cylinders when the material and groove design suit compressed air and lubricating conditions.
For hydraulic cylinder assemblies, a U-cup seal is often used with a wiper seal, a buffer seal, guide rings, and a piston seal set. CORASEALS can quote the separate U-cup seal or a full seal kit when the cylinder dimensions and seal positions are provided. View hydraulic cylinder seal kits for related products if you need a complete cylinder sealing package.
Not every U-cup material suits every hydraulic system. Polyurethane U-cup seals can be a good choice for high pressure and wear resistance. However, some polyurethane grades are sensitive to hot water, steam, or certain hydraulic fluids. NBR U-cup seals work well in mineral oil but are not suitable for all synthetic fluids or high temperature conditions. FKM U-cup seals can handle higher temperatures and more aggressive fluids, but FKM is not always the best choice for high speed or abrasive conditions. HNBR offers a balance of heat resistance and oil resistance. Each material grade must be checked against the actual fluid and temperature range.
CORASEALS does not publish a universal pressure rating for all U-cup seals. The pressure limit depends on the profile, material, groove clearance, extrusion gap, back-up ring, and operating temperature. For high pressure applications, a U-cup seal may require a back-up ring to prevent extrusion.
CORASEALS provides U-cup seals as part of a wider industrial sealing range. We work with hydraulic cylinder repair shops, equipment maintenance teams, seal distributors, and OEM procurement departments. We accept drawings, sample photos, and measured dimensions. We do not claim that a code number automatically matches another supplier part. We check the profile and dimensions before confirming interchange.
We also supply related seals for hydraulic cylinders, including rod seals, piston seals, wiper seals, buffer seals, wear rings, guide rings, O-rings, and back-up rings. This allows you to source multiple cylinder sealing parts with one inquiry instead of switching between suppliers for each seal position.
Use the following checklist for a faster quote.
Send us the seal type, material, ID, OD, groove dimensions, operating temperature, pressure, medium, speed, drawing, sample photo, and required quantity. Include a sample if you are not sure about the profile. This helps us confirm the right U-cup seal instead of guessing from an incomplete part number.
What is a U-cup seal used for?
A U-cup seal is used for rod sealing or piston sealing in hydraulic and pneumatic cylinders. The U-shaped cross section allows fluid pressure to energize the seal lips against the sealing surface.
Which material is best for a U-cup seal?
The material depends on the fluid, temperature, pressure, and speed. Polyurethane and TPU offer good wear resistance. NBR is common in mineral oil. FKM is used for higher temperatures or chemical resistance. HNBR can suit hot oil and demanding mobile hydraulic conditions.
How do I measure a U-cup seal?
Measure the inside diameter, outside diameter, and height or width. For a cylinder sealing position, also provide the rod diameter, bore diameter, groove ID, groove OD, groove width, and groove depth.
Are UN and UHS U-cup seals interchangeable?
Do not assume interchange from the code alone. UN, UHS, UPH, and DH profile codes vary across catalogs. CORASEALS confirms the cross section, lip type, dimensions, and material before quoting.
Can CORASEALS supply U-cup seals in custom sizes?
Yes. Send the seal type, material, ID, OD, width, operating conditions, drawing, sample photo, and required quantity. We can quote based on existing tooling or custom dimensions when the details are clear.
For U-cup seal sourcing, contact CORASEALS with your rod diameter, bore diameter, groove dimensions, fluid, pressure, speed, temperature, and quantity. If you have a drawing or sample, attach it to the inquiry.
