A combi oil seal is a sealing assembly that combines a primary oil-retaining lip with one or more additional features, commonly a dust-exclusion lip or protective component. Its purpose is to help retain lubricant and limit the entry of contaminants around a rotating shaft. Exact designs vary by manufacturer and application, so “combi oil seal” does not identify one universal construction or performance rating. At TEBIETE, we recommend selecting the seal from the shaft, housing, operating conditions, and contamination risks—not from the name alone.
This guide is for engineers, maintenance teams, and procurement professionals evaluating seals for rotating equipment. It is particularly relevant when a standard oil seal may not provide the required combination of lubricant retention and external contamination control. Buyers comparing replacement parts or sourcing a custom sealing solution can also use the selection steps below to prepare a clearer inquiry.
A conventional radial oil seal typically uses a flexible sealing lip that contacts a rotating shaft, with a spring often used to maintain lip contact. A combi design adds another sealing or protective element, such as a secondary lip that helps keep dust, moisture, or other external contaminants away from the primary sealing area. The additional element may be integrated into the seal or combined with a separate protective structure, depending on the design.
These elements work together, but they do not eliminate every source of leakage or contamination. Shaft condition, installation, lubrication, pressure, temperature, and alignment can all influence sealing performance. The appropriate design therefore depends on the machine’s actual operating environment and the seal maker’s specified limits.
Combi oil seals are available in different configurations and materials. The primary lip material must be compatible with the lubricant and operating temperature, while the outer structure may use an elastomer, a metal case, or a combination of materials. Common elastomer families in oil-seal applications include nitrile rubber (NBR) and fluoroelastomer (FKM), but neither should be selected by name alone: grades and formulations differ, and compatibility should be confirmed against the specific fluid and conditions.
Some designs use a garter spring to support lip contact; others may omit it or use a different arrangement. A secondary lip may provide additional exclusion, but its geometry and contact conditions vary. Ask for a cross-section or product drawing when the construction matters to your application.
Combi seals may be considered in gearboxes, agricultural machinery, construction equipment, wheel or axle assemblies, pumps, and other rotating systems exposed to dirt or moisture. The best fit depends on the contaminant, rotational movement, lubrication method, and available installation space. An environment with abrasive dust may call for a different exclusion strategy from an application exposed mainly to occasional splashes.
For a replacement, the existing seal is useful evidence but not always a complete specification. A previous seal may have failed because of shaft wear, incorrect installation, unsuitable material, or a changed duty cycle. Where possible, compare the part with the equipment drawing and verify dimensions and operating conditions before ordering.
Start with the interface dimensions, then check operating conditions and the risks the additional sealing element needs to address. This sequence helps prevent a common sourcing problem: choosing a seal that appears similar but does not fit the housing, shaft, or service conditions. We recommend sharing the following information with your supplier before requesting a quotation.
Record the shaft diameter, housing bore, and available axial width using the equipment drawing or careful measurement. Include tolerances where available, and note whether the shaft surface has grooves, corrosion, or a wear track. As a clearly illustrative inquiry example—not a recommended seal specification—a buyer might report a 50 mm shaft diameter, a 72 mm housing bore, and 10 mm of available axial space.
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Provide the lubricant type, expected operating temperature, shaft speed, direction of rotation, and any pressure or axial movement. Use units consistently, such as °C for temperature and rpm for rotational speed, and distinguish normal operation from short-duration peaks. For example, an inquiry might state 80 °C and 1,500 rpm as measured or design conditions; those figures are examples only and do not indicate a universal combi seal rating.
Describe whether the seal faces dry dust, mud, water spray, cleaning fluids, or another contaminant, and how frequently exposure occurs. Explain whether the priority is lubricant retention, contaminant exclusion, or a balance of both. This helps the supplier assess whether a secondary lip is appropriate and whether an alternative protective arrangement should be considered.
Seal life can be affected by shaft finish, hardness, runout, misalignment, and installation damage. Confirm the shaft condition at the sealing track and check that installation tooling will avoid cutting or rolling the lip. Follow the selected seal’s installation guidance, including any requirements for lip lubrication and orientation.
| Information to provide | Why it matters |
|---|---|
| Shaft diameter, housing bore, and width | Confirms fit and available installation space. |
| Lubricant, temperature, speed, and pressure | Supports material and design suitability checks. |
| Contaminants and exposure conditions | Clarifies the need and type of external exclusion. |
| Drawing, sample, or existing part details | Helps identify the configuration and dimensional requirements. |
| Order quantity and delivery destination | Allows the supplier to discuss quotation and logistics. |
The price of a combi oil seal depends on factors such as size, material, construction, tooling needs, order quantity, and inspection or packaging requirements. Minimum order quantities and lead times are supplier- and product-specific, so they should be confirmed for the exact part rather than assumed from a general product category. For a custom or non-standard design, a drawing review and sample approval may be part of the sourcing process.
To compare quotations fairly, confirm that each supplier is quoting the same dimensions, material, sealing configuration, and quantity. Ask whether the offer is for a standard item or a customized part, and clarify what documentation and packaging are included. This makes it easier to distinguish a true like-for-like price from a lower quote based on a different specification.
Choose a supplier that can discuss the application rather than simply match an outside diameter. Ask whether they can review drawings, identify missing operating information, explain material options, and confirm the proposed construction before production. For repeat orders, agree on a controlled part reference and the documents or sample details needed to keep future purchases consistent.
At TEBIETE, we support B2B inquiries for oil-sealing products, including combi oil seal requirements. Sharing a drawing, sample details, or a complete operating-condition summary gives us a stronger basis to review fit and discuss available manufacturing options. We can also help identify which missing measurements or service details need confirmation before a final specification is agreed.
A combi oil seal combines lubricant-retaining and additional protective functions, but its construction and capabilities differ between designs. Select it by verifying dimensions, lubricant compatibility, temperature, speed, pressure, shaft condition, and the contaminants present. There is no single material or configuration that is right for every rotating application.
To move forward, prepare the shaft and housing dimensions, describe the service conditions, and share a drawing or sample reference with your supplier. Ask the supplier to confirm the proposed material and construction, as well as quotation quantity and lead time, before placing an order. Contact TEBIETE with these details to discuss a combi oil seal solution for your application.
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