Backup Ring: Thickness 1-3 mm typically, Hardness 70-95 Shore D

Component Specifications

Definition

A backup ring is an annular component installed adjacent to a primary seal (such as an O-ring or U-cup) in hydraulic or pneumatic systems. Its primary function is to provide mechanical support to the seal, preventing it from extruding into the clearance gap between mating parts under high pressure, extreme temperature fluctuations, or dynamic conditions. This extends seal life and maintains system integrity by ensuring the seal remains properly positioned and functional.

Working Principle

The backup ring works by filling the clearance gap between the piston rod and cylinder bore or gland. When system pressure increases, it acts as a physical barrier, absorbing pressure and preventing the softer seal material from deforming and extruding into this gap. It distributes mechanical stress and maintains the seal's geometry under operational loads.

Materials

Typically made from rigid, low-friction, and pressure-resistant materials. Common specifications include: PTFE (Polytetrafluoroethylene) for chemical resistance and low friction, Nylon (Polyamide) for general durability, PEEK (Polyetheretherketone) for high-temperature applications, Polyurethane for abrasion resistance, and filled PTFE composites (e.g., glass-filled, bronze-filled) for enhanced strength.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Hardness	70-95 Shore D
Thickness	1-3 mm typically
Inner Diameter	Matches piston rod diameter
Outer Diameter	Fits within cylinder bore/gland
Pressure Range	Up to 600 bar (8700 psi)
Temperature Range	-40°C to +200°C (material-dependent)

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 3601-3, DIN 3771, SAE J515

Parent Products

This component is used in the following industrial products

Piston Rod & Seal

A critical assembly consisting of the piston rod and its sealing system that prevents fluid leakage while transmitting linear motion in drive mechanisms.

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Engineering Analysis

Risks & Mitigation

Seal extrusion without backup leading to leakage
Incorrect installation causing ring damage or misalignment
Material incompatibility with system fluids
Excessive clearance gaps reducing effectiveness
Thermal degradation in high-temperature environments

FMEA Triads

Trigger: Insufficient backup ring hardness or thickness
Failure: Seal extrusion into clearance gap under high pressure
Mitigation: Use reinforced materials (e.g., glass-filled PTFE) and ensure proper dimensional specs

Trigger: Chemical incompatibility with hydraulic fluid
Failure: Backup ring swelling, cracking, or loss of mechanical properties
Mitigation: Select chemically resistant materials (e.g., virgin PTFE) and verify fluid compatibility charts

Trigger: Improper installation or misalignment
Failure: Uneven wear, seal distortion, or system leakage
Mitigation: Follow manufacturer installation guidelines, use installation tools, and inspect during assembly

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Typically IT7/IT8 per ISO 286, with precise inner/outer diameter and thickness controls

Test Method

Pressure testing per ISO 3601-3, dimensional inspection via CMM, material verification per ASTM standards

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Backup Ring

1 company lists this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

Ningbo XiaYi Electromechanical Technology Co., Ltd.

Ningbo, Zhejiang, CN

Founded 2006100~200 staff

IATF16949

Also makes: Piston & Rod

Listed on the company's own website · profile compiled by CNFX from public sources

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Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

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Shaft Bearing

Precision component supporting rotating shafts in vibration motors to reduce friction and maintain alignment.

Seal Groove

Precision-machined groove in aluminum bearing housings designed to accommodate sealing elements for fluid containment and contamination prevention.

Frequently Asked Questions

When is a backup ring necessary?

Backup rings are essential in high-pressure systems (typically above 150 bar), with large clearance gaps, under extreme temperature swings, or in dynamic applications to prevent seal failure.

Can backup rings be used with all seal types?

Primarily used with elastomeric seals like O-rings, U-cups, and rod seals; not typically needed with metal seals or self-supporting designs.

How do I select the right backup ring material?

Choose based on operating conditions: PTFE for chemical/thermal resistance, Nylon for cost-effectiveness, PEEK for high temperatures, and consider filled composites for wear resistance.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Backup Ring