INDUSTRY COMPONENT

Eccentric Shaft

A rotating shaft with offset centerline used to convert rotary motion into reciprocating motion in oscillation mechanisms.

Component Specifications

Definition
An eccentric shaft is a mechanical component featuring a cylindrical journal whose geometric center is deliberately offset from the shaft's rotational axis. This design creates an eccentricity (throw) that transforms continuous rotary input into controlled linear or oscillatory output motion when integrated into mechanisms like linkages, cams, or cranks. It is fundamental in applications requiring precise periodic displacement, such as vibrating screens, compactors, and certain types of pumps or engines.
Working Principle
The working principle relies on the offset between the shaft's rotational center and the eccentric journal's center. As the shaft rotates, this offset causes the journal to trace a circular path, imparting a reciprocating or oscillating motion to any component (e.g., a connecting rod or bearing) mounted on it. The amplitude of oscillation is determined by the eccentricity distance (throw), while frequency is controlled by rotational speed.
Materials
Typically manufactured from high-strength alloy steels (e.g., AISI 4140, 4340) or carbon steels, often heat-treated (quenched and tempered) to achieve surface hardness of 45-55 HRC and core toughness. Corrosion-resistant coatings or stainless steels (e.g., 17-4 PH) may be used in harsh environments.
Technical Parameters
ParameterTypical rangeNotes & selection driver
Length200–2000 mmOverall length including journals and bearing seats.
Hardness45–55 HRCSurface hardness after heat treatment; core hardness typically 28–35 HRC.ISO 18265
Shaft Diameter25–150 mmDiameter of the main bearing journals; tolerance class h6 or h7.ISO 286-2
Surface Finish0.4–1.6 µm RaOn bearing journals and eccentric surfaces; finer finish for high-speed applications.ISO 1302
Runout Tolerance0.02–0.05 mmTotal indicated runout (TIR) of eccentric journals relative to main bearing axis.ISO 1101
Eccentricity (Throw)5–50 mmDistance between center of main journal and center of eccentric journal; determines stroke.
Dynamic Load Capacity10–200 kNMaximum allowable dynamic load at rated speed; depends on bearing size and material.ISO 76
Rotational speed100–1500 rpmOutside this window: Above 1500 rpm may cause excessive vibration and bearing wear; below 100 rpm may lead to inadequate lubrication film.
Operating temperature-20 to 120 °COutside this window: Above 120 °C may degrade lubricant and cause thermal expansion; below -20 °C may cause brittle fracture in some steels.
LubricationISO VG 46–220 oil or NLGI 2 greaseOutside this window: Inadequate lubrication leads to scuffing and premature failure; wrong viscosity may cause overheating.
Misalignment≤0.1 mm parallel offset, ≤0.5° angularOutside this window: Excessive misalignment induces bending stresses and accelerates bearing and seal wear.

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 286-2, ISO 1101, ISO 1302, ISO 18265, ISO 76

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Fatigue cracking due to cyclic loading
  • Bearing seizure from inadequate lubrication
  • Imbalance causing excessive vibration
  • Misalignment leading to premature wear
FMEA Triads
Trigger: Cyclic stress exceeding material endurance limit
Failure: Fatigue fracture at the eccentric journal fillet
Mitigation: Implement finite element analysis (FEA) during design, use shot peening to induce compressive residual stresses, and specify regular non-destructive testing (NDT).
Trigger: Contaminated or insufficient lubrication
Failure: Bearing seizure on the eccentric journal, causing shaft scoring and overheating
Mitigation: Use sealed bearings or automatic lubrication systems, establish preventive maintenance schedules, and monitor oil quality.

Compliance & Inspection

Tolerance
Geometric tolerances per ISO 1101:2017, with eccentricity tolerance typically ±0.1 mm and runout ≤ 0.05 mm.
Test Method
Dimensional inspection via CMM, hardness testing per ISO 6508, dynamic balancing to ISO 1940-1 G6.3 grade, and NDT (ultrasonic or magnetic particle) for crack detection.

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.

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Manufacturers of Eccentric Shaft

Manufacturer profiles associated with Eccentric Shaft.

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Frequently Asked Questions

What is the primary function of an eccentric shaft?

To convert continuous rotary motion into controlled linear or oscillatory motion through an offset journal design.

How is eccentricity measured and specified?

Eccentricity (throw) is the radial distance between the shaft's rotational axis and the eccentric journal's center, typically specified in millimeters.

What maintenance is required for eccentric shafts?

Regular lubrication of bearings, monitoring for wear or imbalance, and checking alignment and fastening to prevent fatigue failure.

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.

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