Synchronizer

Features & Benefits

• Smooth, quiet gear shifts
  By synchronizing speeds before dog teeth mesh, synchronizers prevent gear clash and grinding, reducing noise and vibration compared with non-synchromesh systems.

• Reduced driver effort and improved comfort
  Well-designed synchronizers lower required shift force and make shifts more forgiving, which is especially important in heavy-duty trucks and buses operating for long hours.

• Flexible friction technology
  DD Gear can work with brass/bronze, sintered steel and composite friction linings (carbon, molybdenum, sintered metallic) depending on torque level, oil type and target life, following the trends used in modern transmissions.

• Single-cone to multi-cone designs
  We support single-cone, double-cone and multi-cone synchronizer geometries, allowing customers to increase effective friction area and tune shift force and capacity for high-torque applications.

• Precision cone and tooth geometry
  Accurate cone angles, runout and tooth profiles are critical for consistent friction torque and reliable blocking. DD Gear applies gear-style measurement discipline to synchronizer cones and rings to ensure repeatable contact and shift characteristics.

• From prototype rings to series supply
  We support early gearbox development with small prototype batches (including alternative friction materials), then stabilize the process for SOP and series production with full traceability and inspection.

Technical Specifications

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

Applications

• Passenger-car and light-commercial manual transmissions
  Synchronizer rings and cones for 5-, 6- and higher-speed car gearboxes, supporting quiet, comfortable shifting for everyday driving.

• Heavy-duty truck and bus gearboxes
  High-capacity synchronizer components designed for large inertia and torque, often using multi-cone or advanced friction materials to keep shift forces manageable.

• Automated manual and dual-clutch transmissions (AMT/DCT)
  Synchronizers combined with electronic shift control to deliver fast, repeatable shifts in commercial and performance applications.

• Transfer cases and axle inputs
  Synchronized engagement of 4×4 modes, PTO drives or axle disconnect systems to reduce clash and noise.

• Off-highway and specialty vehicles
  Agricultural tractors, construction machinery and specialty vehicles where robust, easy-to-shift transmissions are essential for operator comfort and productivity.

Gear Manufacturing Process

Every custom synchronizer 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 synchronizer components are kept as matched sets (ring + cone) where required; mixing parts from different sets may change friction behavior.

• During gearbox assembly, carefully control cone clearance, axial positions and dog-tooth backlash, following the design specifications. Incorrect settings can cause hard shifts, clash or premature wear.

• Use the recommended transmission oil; friction materials are tuned for specific oil chemistry and viscosity. Changing oil type can significantly affect shift feel and wear.

• Avoid repeated abusive shifting (e.g., forcing the lever through without clutch) which can overload rings and dog teeth even if the synchronizer is correctly sized.

• During service, inspect friction surfaces and dog teeth for polishing, pitting or chipping; increasing shift effort or grinding noise is a sign that synchronizers may be approaching their wear limit.

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 synchronizer quotation?
We normally need gearbox drawings and 2D/3D data for the synchronizer rings, cones and hubs; target torque and speed range; oil type; desired shift force and synchronization time; target mileage or life; and annual volume.

Q2: Can you supply complete synchronizer assemblies?
DD Gear primarily supplies synchronizer rings and related precision components (cones, hubs, sometimes keys). Full assemblies with sleeves, hubs, bearings and shift mechanisms can be discussed, but most customers integrate the complete synchronizer unit themselves.

Q3: How do I choose between brass, sintered and carbon friction linings?
Brass/bronze rings are proven and cost-effective for moderate torques; sintered steels and composite linings (molybdenum, carbon) offer higher thermal capacity, better wear resistance and more consistent friction for high-torque transmissions. The best choice depends on torque, oil, duty cycle and target life.

Q4: Do you support multi-cone synchronizers?
Yes. We can manufacture single-cone, double-cone and multi-cone rings and mating parts according to your design, helping to increase friction area and reduce required shift force.

Q5: How do synchronizers improve driver comfort compared with non-synchro gearboxes?
Synchronizers equalize speeds before engagement, so drivers no longer need double-clutching and do not hear gear clash; shifts are smoother, quicker and quieter, with less risk of gear damage.