Differential Case for Front Differential Assembly

Product Specifications

Technical details and manufacturing context for Differential Case

Definition

The differential case is a critical structural component of the front differential that serves as the protective housing for the differential gears, pinions, and other internal components. It provides mounting points for bearings, seals the lubricant within the differential, and transfers torque from the ring gear to the axle shafts while withstanding significant mechanical stresses and thermal loads. The case is typically manufactured from cast iron, aluminum alloy, or forged steel, with material selection depending on the required strength, weight, and cost. For example, ductile iron grade QT400-18 (per GB/T 1348) offers a minimum tensile strength of 400 MPa, yield strength of 250 MPa, elongation of 18%, and hardness in the range of 156–197 HBW. The operating temperature range is typically -40°C to 120°C, beyond which material properties may degrade. The case features bearing bores with diameters typically between 80 and 120 mm, machined to an H7 tolerance (ISO 286-2) to ensure proper bearing fit. The flange diameter ranges from 150 to 200 mm, and the overall length from 200 to 300 mm. The weight typically falls between 5 and 10 kg, depending on size and wall thickness. Critical machining requirements include a flange face flatness of 0.05 mm (ISO 1101) and a surface finish of Ra 3.2 μm (ISO 1302) on machined surfaces. These specifications are reference values; actual values must be confirmed for the specific vehicle model and application. The differential case must be verified against the manufacturer's specifications to ensure proper fit, function, and durability.

Working Principle

The differential case rotates with the ring gear, transmitting torque to the differential gears housed inside. It maintains proper alignment of the internal components, contains lubricating oil to reduce friction and wear, and provides structural integrity to withstand the torsional forces generated during vehicle operation, especially during cornering when differential action occurs. The case also serves as a mounting point for bearings, which support the assembly within the axle housing. As the ring gear turns, the case transfers rotational motion to the differential gears, allowing the axle shafts to rotate at different speeds when needed. The case must be precisely machined to ensure correct gear meshing and bearing alignment, and it must be sealed to prevent lubricant leakage and contamination.

Common Materials

Cast Iron, Aluminum Alloy, Forged Steel

Technical Parameters

Parameter	Typical range	Notes & selection driver
Material	QT400-18	Ductile iron grade for strength and toughnessGB/T 1348
Tensile Strength	≥400 MPa	Minimum for QT400-18GB/T 1348
Yield Strength	≥250 MPa	Minimum for QT400-18GB/T 1348
Elongation	≥18 %	Minimum for QT400-18GB/T 1348
Hardness	156–197 HBW	Typical for QT400-18GB/T 1348
Operating Temperature	-40–120 °C	Exceeding range may degrade material properties
Bearing Bore Diameter	80–120 mm	Typical range for front differential cases
Flange Diameter	150–200 mm	Mounting flange size
Overall Length	200–300 mm	Envelope dimension
Weight	5–10 kg	Depends on size and wall thickness
Bearing Bore Tolerance	H7	Ensures proper bearing fitISO 286-2
Flange Face Flatness	0.05 mm	Critical for sealingISO 1101
Surface Finish	Ra 3.2 μm	On machined surfacesISO 1302

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Case Body
The case itself: encloses and protects the internal parts.
Bearing Journals Part
Provide mounting surfaces for differential bearings to support rotation

Material: Hardened Steel
Ring Gear Flange Part
Mounting surface for attaching the ring gear to transfer torque

Material: Cast Iron or Forged Steel
Axle Shaft Openings Part
Allow passage of axle shafts into the differential assembly

Material: Same as main case material
Filler/Drain Plug Bosses Part
Provide threaded openings for lubricant filling and draining

Material: Same as main case material

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Differential Case.

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Front Differential

View system integration details

Rear Differential

View system integration details

Manufacturers of Differential Case

Manufacturer profiles associated with Differential Case.

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Frequently Asked Questions

What is the function of a differential case?

The differential case encloses and protects the differential gears and pinions, provides mounting points for bearings, seals the lubricant, and transfers torque from the ring gear to the axle shafts while withstanding mechanical stresses and thermal loads.

What materials are commonly used for differential cases?

Common materials include cast iron, aluminum alloy, and forged steel. The specific grade, such as ductile iron QT400-18, is selected based on strength, weight, and cost requirements.

What are typical dimensional specifications for a front differential case?

Typical bearing bore diameter is 80–120 mm with H7 tolerance, flange diameter 150–200 mm, overall length 200–300 mm, and weight 5–10 kg. These are reference ranges; confirm exact values for your application.

Why is it important to verify specifications with the manufacturer?

Specifications such as material grade, tolerances, and surface finish must match the vehicle's requirements to ensure proper fit, function, and durability. The manufacturer or supplier can provide model-specific data and confirm compliance with relevant standards.

Data Basis

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pressure:	0 to 3 bar internal, 0 to 10 bar external (housing pressure rating)
other spec:	Max torque capacity: 500-5000 Nm (model dependent), Lubricant viscosity range: SAE 75W-90 to SAE 85W-140
temperature:	-40°C to 150°C (operating), -50°C to 180°C (peak)

Differential Case

Product Specifications

Industry Taxonomies & Aliases

Applied To / Applications

Industrial Ecosystem & Supply Chain Structure

Application Fit & Sizing Matrix

Reliability & Engineering Risk Analysis

Compliance & Manufacturing Standards