Spool Body: Temperature Range -40°C to 120°C

Q: What causes spool body sticking in hydraulic valves?

Contamination (particles >5μm), thermal expansion mismatch, improper clearance, or varnish buildup from degraded fluid.

Component Specifications

Definition

The spool body is the core moving element within a precision hydraulic valve, typically a ground and polished cylindrical component with precisely machined lands and grooves. It slides axially within the valve bore to open, close, or meter fluid passages between ports, controlling direction, flow rate, and pressure of hydraulic fluid in systems requiring high accuracy and repeatability.

Working Principle

Operates through axial displacement within a matched bore, where its lands block or uncover port openings. Pressure differentials across the spool create hydraulic forces balanced by control pressures or springs, enabling precise modulation of fluid flow paths between inlet, outlet, and actuator ports.

Materials

Case-hardened alloy steel (e.g., AISI 8620, 4140) or stainless steel (17-4PH, 440C) with surface hardness 58-62 HRC, core toughness 28-32 HRC. Chrome plating (0.02-0.05mm) or nitriding for wear/corrosion resistance.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Straightness	0.001mm/100mm
Surface Finish	Ra 0.1-0.2μm
Spool Clearance	0.005-0.015mm
Temperature Range	-40°C to 120°C
Diameter Tolerance	±0.002mm
Operating Pressure	Up to 350 bar
Land Width Tolerance	±0.01mm

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 4401, DIN 24342, ISO 10770-1

Parent Products

This component is used in the following industrial products

Precision Hydraulic Valve Spool

A precision hydraulic valve spool is a cylindrical metal component that slides within a valve body to regulate hydraulic fluid flow, pressure, and direction.

View Product Details

Engineering Analysis

Risks & Mitigation

Contamination-induced erosion
Thermal galling
Cavitation damage
Fatigue cracking at stress concentrators

FMEA Triads

Trigger: Hard particle contamination in fluid
Failure: Abrasive wear on lands leading to increased leakage
Mitigation: Install 3μm absolute filtration, specify hardened/chrome-plated surfaces

Trigger: Misalignment during assembly
Failure: Uneven wear and binding
Mitigation: Use precision alignment fixtures, verify bore concentricity <0.005mm TIR

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Geometric tolerances per ISO 1101, size tolerances per ISO 286

Test Method

Leakage test per ISO 10770-1, pressure cycling per ISO 6403

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

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Inspection readiness

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

Supplier transparency

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Manufacturers of Spool Body

Manufacturer profiles associated with Spool Body.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What causes spool body sticking in hydraulic valves?

Contamination (particles >5μm), thermal expansion mismatch, improper clearance, or varnish buildup from degraded fluid.

How is spool body wear measured?

Through dimensional inspection of lands/grooves, surface roughness testing, and leakage flow tests per ISO 10770-1.

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.

Spool Body