INDUSTRY COMPONENT

Float Arm

A mechanical arm in fuel level sensors that moves with float buoyancy to measure fuel volume.

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Component Specifications

Definition
The float arm is a precision mechanical component in automotive fuel level sensors that converts the vertical displacement of a buoyant float into rotational movement. This movement is transmitted to a variable resistor or Hall effect sensor to generate electrical signals proportional to fuel volume. It operates within the fuel tank environment and must maintain accuracy across temperature variations, vehicle motion, and fuel slosh conditions.
Working Principle
Buoyancy principle: The float rises/falls with fuel level, causing the attached arm to pivot. This rotational movement changes resistance in a potentiometer or alters magnetic field position for Hall effect sensors, creating voltage signals corresponding to fuel volume.
Materials
Stainless steel (AISI 304/316) for corrosion resistance, aluminum alloys (6061-T6) for lightweight applications, or engineered plastics (POM, PEEK) with fuel compatibility. Hinge pins typically use brass or stainless steel.
Technical Parameters
  • Length 80-250mm
  • Accuracy ±2-5% of full scale
  • Load Capacity 5-20N
  • Rotation Angle 0-90 degrees
  • Fuel Compatibility Gasoline, Diesel, Ethanol blends
  • Operating Temperature -40°C to +125°C
Standards
ISO 2575, DIN 72785, SAE J1930

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Float Arm.

float arm fuel level sensor automotive component fuel gauge buoyancy sensor vehicle fuel system fuel tank sensor Float Arm in Motor Vehicle Manufacturing

Parent Products

This component is used in the following industrial products

Fuel Level Sensor

A sensor that measures and monitors the amount of fuel remaining in a fuel tank.

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Engineering Analysis

Risks & Mitigation
  • Fuel leakage if seals fail
  • Inaccurate readings from stuck/worn components
  • Electrical shorts in wet environments
  • Material incompatibility with alternative fuels
FMEA Triads
Trigger: Hinge corrosion/wear
Failure: Sticking or binding movement
Mitigation: Use corrosion-resistant materials, regular maintenance checks, protective coatings
Trigger: Float saturation/leakage
Failure: Buoyancy loss causing reading errors
Mitigation: Sealed float designs, material testing for fuel compatibility, moisture barriers
Trigger: Electrical contact degradation
Failure: Erratic or no signal output
Mitigation: Gold-plated contacts, sealed connectors, redundant contact designs

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
±0.5mm dimensional tolerance, ±1° angular alignment
Test Method
Buoyancy testing in simulated fuels, cycle testing (50,000+ cycles), temperature cycling (-40°C to +125°C), vibration testing per automotive standards

Buyer Feedback

★★★★☆ 4.8 / 5.0 (28 reviews)

"Found 34+ suppliers for Float Arm on CNFX, but this spec remains the most cost-effective."

"The technical documentation for this Float Arm is very thorough, especially regarding technical reliability."

"Reliable performance in harsh Motor Vehicle Manufacturing environments. No issues with the Float Arm so far."

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Enclosure
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Frequently Asked Questions

What causes float arm failure in fuel sensors?

Common failures include hinge wear from continuous movement, material degradation from fuel additives, float saturation altering buoyancy, and electrical contact corrosion in potentiometer-based designs.

How does temperature affect float arm accuracy?

Temperature changes alter fuel density (affecting buoyancy) and cause material expansion/contraction. Modern designs compensate through material selection and calibration curves.

Are float arms interchangeable between vehicle models?

Not universally. Differences in tank geometry, mounting points, electrical interfaces, and fuel types require model-specific designs, though some aftermarket manufacturers offer compatible versions.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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Filter Substrate Flocking/Low-Friction Coating