Crown Wheel and Pinion

Features & Benefits

• Efficient 90° torque transfer and final reduction
  Crown wheel and pinion sets change the direction of rotation from the propshaft to the axle shafts and provide the final reduction ratio, converting engine or motor speed into the wheel torque needed for launch, hill-climbing, and towing.

• High torque capacity with compact size
  Spiral bevel and hypoid tooth forms offer higher contact ratios and larger tooth overlap than straight bevel gears, enabling them to transmit higher torque in a compact housing – ideal for axles and transaxles with strict space envelopes.

• Smooth, quiet running
  Curved teeth and progressive engagement spread the load over multiple teeth, reducing noise and vibration at highway speeds. Properly ground or lapped tooth surfaces further improve NVH performance.

• Matched gear sets with controlled contact pattern
  Crown wheel and pinion are manufactured as a matched pair, with tooth contact patterns controlled through cutting, heat treatment, and finishing (grinding or lapping). This ensures stable backlash, contact position, and load sharing under varying torque and deflection.

• Flexible ratios for performance and efficiency tuning
  By choosing different tooth combinations, OEMs can fine-tune launch feeling, pulling power, and cruising rpm for various vehicles and tire sizes, whether targeting fuel economy, range, or acceleration.

• Custom materials and heat treatment
  DD Gear selects alloy steels and heat-treatment processes (carburizing, quench-and-temper, shot peening, etc.) according to duty cycle, axle load, and life targets to resist pitting, scuffing, and tooth-root fatigue.

• Prototype to series production
  From small pilot batches for new axle or e-axle development to mass production with controlled processes and inspection plans, we support customers across the full program lifecycle.

Technical Specifications

Final values will be defined according to your drawings and performance requirements.

Applications

• Passenger car and light-truck axles
  Final drive gear sets in rear-wheel, front-wheel, and all-wheel-drive vehicles, converting transmission or e-motor output into wheel torque and enabling differential action.

• Heavy truck and bus drive axles
  High-torque crown wheel and pinion sets for drive axles in long-haul trucks, buses, and vocational vehicles, where durability under high loads and long mileage is critical.

• Agricultural and construction machinery
  Differential and final drive sets in tractors, harvesters, wheel loaders, and other off-highway machines requiring high torque at low ground speeds and robust, contamination-tolerant design.

• EV e-axles and electrified drivelines
  Crown wheel and pinion sets adapted for e-axles and electric drive units, working with high-speed e-motors and focusing on efficiency and low NVH in compact housings.

• Industrial gearboxes and test rigs
  Spiral bevel / hypoid gear sets used in right-angle gearboxes and differential test rigs where high torque and smooth running are required.

Gear Manufacturing Process

Every custom crown wheel and pinion is produced under a controlled gear manufacturing route designed for precision and durability. A typical process flow is:

1. Forging or bar cutting of shaft blanks

2. Lathe machining of shaft diameters and reference surfaces

3. Hobbing or shaping of gear teeth

4. Drilling, milling, and other CNC machining operations

5. Heat treatment (such as carburizing, quenching, tempering, nitriding)

6. Shot blasting and stress relief as required

7. Finish machining and grinding of journals and critical surfaces

8. Gear grinding (profile or worm grinding) where accuracy demands it

9. Cleaning and rust prevention treatment

10. Final inspection and packaging for shipment

Precision Gear Customization Process

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

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

Usage & Installation Notes

• Ensure the crown wheel and pinion are kept as matched pairs—do not mix gears from different sets unless they are ground for interchangeability by design.

• During assembly, follow the specified procedures for pinion depth, bearing preload, and backlash adjustment to establish the correct tooth contact pattern and avoid noise or premature wear.

• Use the recommended hypoid gear oil or axle lubricant; incorrect viscosity or additive packages can increase wear and reduce efficiency.

• Avoid shock loading beyond rated torque; repeated wheel hop or harsh clutch engagements may reduce life even if gears are correctly sized.

• During service, inspect tooth flanks for pitting, scoring, and micro-cracks, and check for increased backlash or abnormal noise that may indicate wear or setup drift.

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 a crown wheel and pinion quotation?
We normally need detailed drawings (ring and pinion), target ratio, material and heat-treat specs, axle layout, vehicle type, axle load, duty cycle, and expected annual volume.

Q2: Can you help optimize ratios or tooth geometry?
Yes. Within your platform constraints, we can discuss tooth counts, hypoid offsets, face widths, and heat-treat windows to balance torque capacity, efficiency, and NVH. Final geometry will always be agreed with your engineering team.

Q3: Do you supply complete differentials or only gear sets?
DD Gear focuses on precision gear components. We typically supply the crown wheel, pinion, and related gears/shafts; carriers, housings, bearings, and full differential assemblies are handled by the customer or their system integrator.

Q4: What accuracy and finishing levels can you offer?
We manufacture bevel and hypoid gears to automotive-grade standards and can provide lapped or ground tooth flanks with defined roughness and contact patterns suited to your NVH and durability targets.

Q5: What lead times can we expect for prototypes and SOP?
Prototype sets are typically available about 2–3 weeks after drawing confirmation and tooling readiness. Series lead time depends on quantity, process route, and program schedule, and is confirmed at quotation.

Q6: Can you provide inspection reports and test data?
Yes. We can supply dimensional reports, bevel gear measurement charts, hardness and case-depth records, and contact pattern photos; additional test data can be discussed for specific projects