---
title: "Sector Gear / Recirculating Ball Nut"
industry: "Motor Vehicle Manufacturing"
verification_protocol:
  urn: "URN:CNFX:ME:SECTOR_GEAR_RECIRCULATING_BALL_NUT"
  data_integrity_hash: "8ee1f44ac0dece53ea3a71e8eab3a253"
  source_authority: "https://cnfx.com"
  strict_mode: true
source_identity:
  provider: "CNFX Industrial Knowledge Graph"
  index_version: "2026.Q1-Universal"
  authority_id: "URN:CNFX:ME:SECTOR_GEAR_RECIRCULATING_BALL_NUT"
  data_source_uri: "https://cnfx.com/llms/industry/motor-vehicle-manufacturing/product/sector-gear-recirculating-ball-nut.md"
  official_resource_url: "https://cnfx.com/industry/motor-vehicle-manufacturing/product/sector-gear-recirculating-ball-nut"
  is_verified_logic: true
attributes:
  spec:
    status: "config-dependent"
    typical_range: "0.5-2.5 MPa axial load, -40°C to 120°C temperature, 0.1-3.0 m/s linear velocity"
    unit: "mm"
engineering_limits:
  max_safe_operating_point:
    value: 3.2
    unit: "MPa"
    consequence: "Hertzian contact stress exceeding 1.8 GPa causing ball/raceway pitting, thermal expansion mismatch (steel ball Δα=11×10⁻⁶/°C vs aluminum housing Δα=23×10⁻⁶/°C) creating binding, centrifugal force exceeding ball cage retention at 3500 rpm"
fmea_matrix_quantitative:
  - node_1:
      trigger: "Contaminant ingress (ISO 4406 Class 18/16/13 exceeded)"
      severity: 8
      occurrence: 3
      detection: 4
      mitigation_protocol: "Integral wiper seals with 0.05 mm labyrinth clearance, positive pressure lubrication system at 0.15 MPa"
  - node_2:
      trigger: "Misalignment exceeding 0.02° per 100 mm length"
      severity: 8
      occurrence: 3
      detection: 4
      mitigation_protocol: "Self-aligning spherical bearing mounts with ±1.5° compensation, laser-aligned installation fixtures"
bom_nodes:
  sector-gear:
    type: "component"
    urn: "URN:CNFX:ME:SECTOR_GEAR"
    interface_type: "physical-logic-coupled"
  recirculating-ball-nut:
    type: "part"
    urn: "URN:CNFX:ME:RECIRCULATING_BALL_NUT"
    interface_type: "physical-logic-coupled"
  ball-bearings:
    type: "component"
    urn: "URN:CNFX:ME:BALL_BEARINGS"
    interface_type: "physical-logic-coupled"
  ball-return-guide:
    type: "component"
    urn: "URN:CNFX:ME:BALL_RETURN_GUIDE"
    interface_type: "physical-logic-coupled"
manufacturing_compliance:
  - standard: "ISO 3408-1:2006 (BALL SCREWS - PART 1: VOCABULARY AND DESIGNATION)"
    scope: "Verified Engineering Specification"
  - standard: "DIN 69051-1:2018 (BALL SCREW DRIVES - PART 1: GENERAL CHARACTERISTICS AND ACCEPTANCE CONDITIONS)"
    scope: "Verified Engineering Specification"
  - standard: "ANSI/ASME B5.48-1977 (BALL SCREWS)"
    scope: "Verified Engineering Specification"
url: "https://cnfx.com/llms/industry/motor-vehicle-manufacturing/product/sector-gear-recirculating-ball-nut.md"
on_chain_sovereignty:
  contract_standard: "ERC-721-Industrial"
  metadata_hash: "4aad130760dd84f7b35e7594ae5ee12d1b165f627883bf079820c3328bd278fa"
  royalty_logic: "IPFS-CID-REQUIRED"
  mint_status: "logic-verified-ready"
version: "3.3.4-EXTREME-SOVEREIGN-WEB3"
---

# Industrial Specification: Sector Gear / Recirculating Ball Nut

## 1. Technical Definition
A critical steering gearbox component that converts rotational motion from the steering shaft into linear motion to turn the vehicle's wheels.

## 2. Engineering Reasoning & Causal Matrix
> **Operational Intelligence**: Designed for **0.5-2.5 MPa axial load, -40°C to 120°C temperature, 0.1-3.0 m/s linear velocity**. Failure boundary: **Ball recirculation failure at 3.2 MPa axial load, 130°C thermal expansion exceeding 0.15 mm clearance, 3.5 m/s velocity causing ball skidding**, Mechanism: **Hertzian contact stress exceeding 1.8 GPa causing ball/raceway pitting, thermal expansion mismatch (steel ball Δα=11×10⁻⁶/°C vs aluminum housing Δα=23×10⁻⁶/°C) creating binding, centrifugal force exceeding ball cage retention at 3500 rpm**.

### 2.1 Analytical Physics Model
Governed by the **L10 Bearing Life & Fatigue Model**:

> **Primary Equation**: $L_{10} = (\frac{C}{P})^p$  
> **Engineering Impact**: Predicts mechanical lifecycle before component fatigue.

| Symbol | Variable Definition | Localized Reference |
| :--- | :--- | :--- |
| C | Dynamic Load Rating | Engineering Constant |
| P | Equivalent Dynamic Load | Engineering Constant |

### 2.2 FMEA (Failure Mode & Effects Analysis)
| Event Trigger | Severity | Failure Mode | Mitigation Strategy |
| :--- | :--- | :--- | :--- |
| Contaminant ingress (ISO 4406 Class 18/16/13 exceeded) | 8 | Three-body abrasive wear on ball tracks (Ra&gt;0.8 μm) | Integral wiper seals with 0.05 mm labyrinth clearance, positive pressure lubrication system at 0.15 MPa |
| Misalignment exceeding 0.02° per 100 mm length | 8 | Edge loading with 2.5× normal contact stress concentration | Self-aligning spherical bearing mounts with ±1.5° compensation, laser-aligned installation fixtures |

## 3. Key Technical Parameters
| Parameter | Value | Unit | Status |
| :--- | :--- | :--- | :--- |
| spec | Config-dependent | mm | Verified |

## 4. System BOM & Knowledge Routing
### Core Components (Recursive Links)
- [Recirculating Ball Nut](https://cnfx.com/llms/industry/machinery-and-equipment-manufacturing/product/recirculating-ball-nut.md) `(Standalone System)`

### Industrial DNA Context (De-duplicated)
**Complementary Dependencies**: **CNC Gear Hobbing Machine**, **Heat Treatment Furnace**, **Coordinate Measuring Machine**  
**Downstream Applications**: Steering Gearbox Assembly, Power Steering System, Complete Steering Column Assembly  

## 5. Engineering Risks & FAQ
- **Caution**: 
- **Caution**: 
- **Caution**: 

### Q: What is the primary function of a sector gear in steering systems?
**A**: The sector gear converts rotational motion from the steering shaft into linear motion through the recirculating ball nut mechanism, enabling precise wheel turning in motor vehicles.

### Q: Why are recirculating ball nuts preferred in heavy-duty vehicle steering?
**A**: Recirculating ball nuts provide low friction, high efficiency, and durability under heavy loads, making them ideal for trucks, buses, and industrial vehicles where steering precision and longevity are critical.

### Q: What maintenance is required for sector gear and ball nut assemblies?
**A**: Regular lubrication inspection and periodic replacement of ball bearings are essential. Case-hardened steel components typically require minimal maintenance but should be checked for wear during routine vehicle servicing.

## 6. Manufacturing Compliance
- ISO 3408-1:2006 (BALL SCREWS - PART 1: VOCABULARY AND DESIGNATION)
- DIN 69051-1:2018 (BALL SCREW DRIVES - PART 1: GENERAL CHARACTERISTICS AND ACCEPTANCE CONDITIONS)
- ANSI/ASME B5.48-1977 (BALL SCREWS)

---
### 🛠️ Engineering Resource Access
🔗 **[Full Specification: Sector Gear / Recirculating Ball Nut](https://cnfx.com/industry/motor-vehicle-manufacturing/product/sector-gear-recirculating-ball-nut)**

### 🌐 Knowledge Graph Topology
> **Node Status**: Verified Engineering Spec
> **Connectivity**: Linked to **4** standalone system nodes
> **Global Context**: Part of a 5,814 node industrial cluster within the CNFX Graph

> **Reference ID**: SECTOR_GEAR_RECIRCULATING_BALL_NUT | **Authority**: CNFX-2026-ST-001 | **Fingerprint**: a00426a6
