INDUSTRY COMPONENT

Shaft Body / Journal

The shaft body/journal is the cylindrical load-bearing section of a ball screw shaft that rotates within bearings to transmit motion and force.

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Component Specifications

Definition
The shaft body, also known as the journal, is the central cylindrical section of a ball screw shaft designed to interface with support bearings. This precision-ground component provides the rotational axis for the screw, maintains alignment under axial and radial loads, and ensures smooth motion transmission by minimizing deflection and vibration. Its dimensional accuracy and surface finish directly impact the ball screw's positioning precision, load capacity, and service life.
Working Principle
The shaft body rotates within precision bearings (typically angular contact or deep groove ball bearings) to convert rotary motion into linear motion via the ball nut. It maintains geometric stability under combined loads (axial, radial, and moment) while providing a low-friction surface for bearing contact. Proper preload and lubrication at the journal interfaces minimize wear and thermal expansion effects.
Materials
High-carbon chromium bearing steel (e.g., SUJ2, AISI 52100), case-hardened steels (e.g., SCr420, 8620), or stainless steels (e.g., SUS440C) with hardness typically 58-62 HRC. Surface treatments may include black oxide coating or phosphate coating for corrosion resistance.
Technical Parameters
  • Hardness 58-62 HRC
  • Roundness ≤ 0.005 mm
  • Length Range 100-6000 mm
  • Straightness ≤ 0.01 mm/m
  • Surface Roughness Ra 0.4 μm or better
  • Diameter Tolerance h5 or h6 (ISO)
Standards
ISO 3408, DIN 69051, JIS B 1192

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Shaft Body / Journal.

ball screw shaft journal precision shaft body linear motion component bearing interface shaft manufacturing standards industrial shaft specifications Shaft Body / Journal Shaft Body / Journal in Machinery and Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Ball Screw Shaft

The precision-ground shaft that forms the core of a ball screw assembly, converting rotary motion into linear motion.

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Engineering Analysis

Risks & Mitigation
  • Brinelling from shock loads
  • Fretting corrosion at bearing interfaces
  • Thermal expansion causing binding
  • Surface degradation from improper lubrication
FMEA Triads
Trigger: Insufficient lubrication or contamination
Failure: Accelerated wear and scoring on journal surface
Mitigation: Implement automatic lubrication systems with filtration; use sealed bearing units
Trigger: Misalignment during installation
Failure: Premature bearing failure and shaft deflection
Mitigation: Use alignment fixtures and dial indicators during assembly; specify proper mounting tolerances
Trigger: Excessive preload or overload
Failure: Permanent deformation (Brinelling) of journal surface
Mitigation: Calculate and verify load ratings; install overload protection devices

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Geometric tolerances per ISO 1101:2017; diameter tolerances per ISO 286-1:2010
Test Method
CMM measurement per ISO 10360-2; surface roughness testing per ISO 4287; hardness testing per ISO 6508-1

Procurement Evaluation Criteria

Not customer reviews or live demand data. These dimensions support RFQ preparation and supplier evaluation.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What is the difference between shaft body and journal in ball screw terminology?

In ball screw context, 'shaft body' refers to the entire cylindrical section, while 'journal' specifically denotes the bearing contact surfaces. However, these terms are often used interchangeably for the load-bearing portion.

How does journal diameter tolerance affect ball screw performance?

Tighter diameter tolerances (e.g., h5 vs. h6) reduce bearing clearance, improving rigidity and positioning accuracy but requiring more precise mounting. Looser tolerances accommodate thermal expansion but may increase vibration.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

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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