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Intermediate Drive Shaft Assembly – Precision for EV | DD Gear

The Intermediate Drive Shaft Assembly – Precision Shaft for EV is a custom shaft module used between the e-axle or transaxle and one of the constant-velocity (CV) axles. It connects the gearbox output to the wheel-side half shaft and helps keep the left and right drive shafts at equal or controlled lengths. This equalization of shaft length and joint angles reduces torque steer and improves straight-line stability and steering feel, especially in high-torque front-drive or e-axle layouts. In typical automotive layouts, the intermediate shaft is splined at both ends and supported by a bearing and bracket on the engine or gearbox side. It transmits motor torque from the transmission or differential to the outer CV axle while allowing service of the CV axle without disturbing the oil seal in the transaxle or differential. For EV applications, the shaft must carry high instantaneous torque from electric motors, operate smoothly over a wide speed range, and maintain alignment of the two half shafts for predictable vehicle behaviour. DD Gear designs and manufactures custom intermediate drive shaft assemblies—including shaft, splines, bearing seats, and flanges—to meet each customer’s drivelines, envelope, and durability targets.

Product Details

FAQ

Features & Benefits

  • Stable torque transfer between e-axle and wheel
    The intermediate drive shaft assembly transmits torque from the EV gearbox or differential to the CV axle, acting as the mechanical link between drivetrain output and the wheel.

  • Improved handling and reduced torque steer
    By creating equal or controlled-length half shafts, the intermediate shaft helps keep inner joint angles similar on both sides of the vehicle, which reduces torque steer and contributes to stable straight-line driving under high motor torque.

  • High strength and fatigue resistance
    Shaft geometry, material selection, and heat treatment are tuned for high torque and repeated loading from acceleration, regenerative braking, and rough road conditions, with attention to spline root strength and journal fillets.

  • Precision-machined splines and bearing journals
    Splined ends, circlip grooves, and bearing journals are machined and ground to tight tolerances for accurate fit and easy assembly with CV joints, bearings, and brackets, supporting smooth rotation and long component life.

  • Integrated support bearing and bracket interface
    The intermediate drive shaft assembly can be supplied with bearing seats and housing interfaces designed for your bracket, helping maintain alignment between gearbox and half shaft under vehicle vibration and thermal expansion.

  • Designed for compact EV packaging
    Shaft length, diameter, and bracket position are optimised to fit within tight EV underbody and motor-bay packaging, coordinating with e-axle housing, suspension geometry, and wheel offset.

  • From prototypes to series production
    DD Gear can provide rapid prototypes for vehicle dynamics and durability testing and then transition to controlled series production with stable quality and documentation.


Technical Specifications

Final data will be defined according to the customer’s drawing and EV duty cycle.

Item Typical Option
Gear Type Solid or tubular steel shaft with splines on one or both ends
Pressure Angle 20° (other angles according to OEM standard)
Material Alloy steels suitable for induction hardening or Q&T (e.g. 40Cr, 42CrMo equivalents, other automotive-grade steels
Heat Treatment
Induction hardening on splines/journals, quench-and-temper, or other processes defined by fatigue and wear requirements
Surface Hardness Typically 50–60 HRC or per drawing

 

Applications

  • Front-drive EVs and hybrid vehicles
    Intermediate shafts between the transaxle output and one of the front half shafts, used to equalize left/right drive shaft lengths and improve ride and handling at high motor torque. 

  • Integrated e-axles with offset motor positions
    Shafts that connect offset motors or gearsets to the wheel-side CV axles in compact drive units, accommodating packaging constraints while maintaining desired shaft angles.

  • Electric light trucks and vans
    Intermediate shaft assemblies used in vehicles with long half-shaft spans or non-symmetric layouts where a separate support bearing is needed for durability.

  • All-wheel-drive EV variants
    Intermediate shafts used in front or rear drivelines where multiple axles or e-axles share torque and equal-length driveshafts are needed to control vehicle response.

 

Gear Manufacturing Process

Gear Manufacturing Process DD Gear

Every intermediate drive shaft assembly is produced under a controlled manufacturing route designed for precision and durability. A typical process flow is:

  1. Forging or bar cutting of shaft blanks

  2. Lathe machining of diameters, bearing journals, and reference surfaces

  3. Milling, drilling, and spline cutting operations

  4. Additional CNC machining as required by geometry

  5. Heat treatment (such as quenching and tempering, induction hardening)

  6. Shot blasting and stress relief as required

  7. Finish machining and grinding of critical mounting surfaces and journals

  8. Cleaning and rust prevention treatment

  9. Final inspection and packaging for shipment

 

Precision Gear Customization Process

Precision Gear Customization Process DD Gear

To support custom intermediate drive shaft assembly projects, DD Gear follows a clear, eight-step customization process:

Step 1 – Requirement Collection
Customers provide design requirements, 2D drawings, 3D models, or physical samples, together with basic duty cycle information (torque, speed, life, installation).

Step 2 – Drawing Design & Optimization
Based on the provided drawings or samples, DD Gear prepares or optimizes detailed manufacturing drawings and shares them with the customer for confirmation.

Step 3 – Quotation
After the drawings and technical points are confirmed, we issue a precise quotation covering tooling, piece price, lead time, and quality requirements.

Step 4 – Tooling & Fixture Preparation
Once the price is confirmed, we arrange tooling and fixture production. Any tooling cost is agreed with the customer in advance and can be offset or refunded after mass orders, according to the commercial agreement.

Step 5 – First Sample Approval
After tooling and fixtures are ready, we manufacture the first sample batch—typically within about 30 days—and ship it to the customer for testing.The customer inspects and validates the samples in their gearbox or test bench and provides feedback on dimensions, performance, and any required adjustments.

Step 6 – Mass Production
When the sample is approved, we start mass production according to the agreed production plan and quality standards.

Step 7 – Finished Product Inspection
After production, we inspect hardness, dimensions, runout, tooth accuracy, and other critical characteristics to ensure full compliance with the drawing and standards.

Step 8 – Shipping Arrangement
Once inspection is passed and shipment is approved by the customer, we arrange booking, packaging, and delivery to the specified destination.


Quality Assurance & Inspection

gear Quality Assurance & Inspection DD Gear

DD Gear applies the same quality philosophy to all precision gears:

  • Quality management systems based on ISO 9001 and IATF 16949

  • Process control from incoming material to final inspection, including:

    • Material certification and chemical composition checks

    • Hardness and case depth verification after heat treatment

    • Gear measurement for profile, lead, pitch, and runout

    • Surface roughness testing on gear flanks and journals

    • Dimensional inspection with calibrated gauges and CMMs

  • Traceability for each batch with inspection records and reports

  • Optional documentation such as PPAP/FAIR packs on request

 

Packaging

gear packaging DD Gear

 

Usage & Installation Notes

  • Ensure correct installation of the support bearing and bracket to maintain shaft alignment relative to the gearbox and half shafts.

  • Confirm that spline engagement depth and circlip retention meet design specifications to avoid disengagement under load. 

  • Use specified torque values for bracket and flange fasteners; incorrect torque may lead to noise, vibration, or premature wear.

  • Verify that left and right half-shaft lengths and joint angles match the intended design, especially after any layout changes or service work.

  • Use the recommended gearbox or e-axle lubricant and maintain oil level and cleanliness.

  • During service, inspect splines, bearing seats, and coating surfaces for corrosion, scoring, or wear, particularly in regions exposed to road splash and salt.

  • Store finished parts in dry, clean conditions with anti-rust protection and avoid impacts on splines and journals.


Company Strength – DD Gear

  • Specialized in small module, high-precision gears and shafts for EVs, humanoid robots, AGVs, and intelligent automation.

  • Integrated manufacturing from forging and machining to heat treatment and gear grinding.

  • Quality systems aligned with automotive standards, with experience supporting OEM and Tier 1 projects.

  • Engineering support covering concept feasibility, DFM reviews, and failure analysis feedback.

  • Global export capability with experience serving customers in multiple countries.

Q1: What information do you need for an intermediate drive shaft assembly quotation?
We normally need 2D drawings (PDF), 3D models (STEP/IGES if available), material and heat treatment requirements, expected annual volume, and basic application data such as vehicle type, torque, shaft layout, and life targets.

Q2: Can you help tune shaft length and layout to reduce torque steer?
Yes. Our engineering team can coordinate with your chassis and drivetrain layout to help define intermediate shaft length and stiffness that support equal or controlled half-shaft lengths and improved straight-line behaviour, while still fitting within packaging limits.

Q3: What lead time should we expect for prototypes and production?
Prototype intermediate drive shaft assemblies are usually available in around 2–3 weeks after final drawing confirmation and tooling readiness. Mass production lead time depends on quantity and process route and will be confirmed during quotation.

Q4: Do you supply the complete CV axle or only the intermediate shaft?
DD Gear mainly focuses on precision shafts, gears, and related components. We typically supply the intermediate drive shaft and associated machined features; complete CV axle assemblies are usually handled by specialized axle or system suppliers.

Q5: What materials and heat treatments can you provide?
We work with a range of alloy steels suitable for induction hardening and quench-and-temper processes. Material grade and heat treatment are defined according to torque, stiffness, and fatigue requirements for your EV platform.

Q6: What is your typical MOQ for intermediate drive shaft assemblies?
MOQ depends on the complexity of the part and tooling. We support flexible MOQ for development and pilot builds, then align batch sizes with your series production plan.

Q7: Can you provide inspection reports with each batch?
Yes. Dimensional inspection reports, hardness records, and other documents can be provided according to your requirements.

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