SANY-SY385 Final Drive Sprocket Rim Assy/Heavy-duty equipment components manufacture-DPW
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Product Specifications
1. Comprehensive Overview and Function
The Final Drive Sprocket Group (often simply called the "Final Drive" or "Travel Motor") is the primary propulsion system for the SANY SY385 excavator. It is a complex, integrated assembly that serves two critical functions:
Power Transmission: It acts as a massive gear reduction system, taking the high-speed, low-torque rotation from the hydraulic motor and converting it into the low-speed, high-torque rotation needed to turn the track and move the massive machine (the SY385 is a 38-40 ton class excavator).
Structural Support: It is a major structural component of the undercarriage. The sprocket engages with the track chain, and the entire final drive assembly is bolted directly to the track frame, bearing significant mechanical loads and shocks during operation.
A failure in the final drive will result in the complete immobilization of the excavator, leading to expensive repairs and significant downtime.
2. Key Components of the "Group"
The term "Group" implies it's a complete, integrated assembly. It primarily consists of two main sub-assemblies:
A. The Motor Group (Reduction Unit):
This is the core of the final drive, containing:
Hydraulic Motor: A high-torque, low-speed motor (often a gerotor or geroller type) that converts hydraulic pressure from the machine's main pump into rotational force.
Multi-Stage Planetary Gear Reduction: A series of planetary gear sets that dramatically increase output torque. This is what allows a relatively small hydraulic motor to move a 40-ton machine.
Output Shaft (Sprocket Shaft): The shaft that exits the reduction unit and to which the sprocket is mounted.
Internal Bearings and Seals: Critical for supporting immense loads and keeping lubricating oil in while keeping contaminants (water, mud, abrasives) out.
B. The Sprocket and Hub:
Sprocket: The large, toothed wheel that directly meshes with the track chain links (the track bushings). It is made from high-carbon, heat-treated alloy steel for extreme wear resistance.
Hub/Flange: The component that connects the sprocket to the output shaft of the motor group, typically via a splined connection and large bolts.
3. Technical Specifications & Identification
Important: The exact part number can vary based on the specific manufacturing year and serial number of your SY385. Always confirm the part number with a SANY dealer using your machine's serial number.
Common SANY Part Number Example: A part number for a complete final drive assembly might look like 60.10007.0032 or follow a similar pattern. A repair kit for seals and bearings might be numbered 60.10007.XXXX.
OEM Equivalent Parts: Major manufacturers like KYB, Kawasaki, or Brevini often supply final drives to OEMs. SANY may use their own or a licensed design. Aftermarket specialists will have their own cross-referenced numbers.
Key Specifications (Approximate for a 38-ton class excavator):
Reduction Ratio: Typically very high, e.g., 50:1 to 60:1.
Sprocket Tooth Count: Common for this size class is 10 teeth.
Mounting Bolt Pattern: The pattern and size of the bolts that attach the final drive to the track frame are critical for fitment.
Spline Count: The number of splines on the output shaft that connects to the sprocket hub.
4. Common Failure Modes and Maintenance
A. Common Failure Modes:
Seal Failure: The most common initial failure. Signs include:
External Leak: Hydraulic oil leaking from the motor shaft seal onto the sprocket or track.
Internal Leak: Contaminated gear oil (milky from water ingress or metallic from gear wear) found when checking the oil level plug.
Bearing Failure: Often a result of seal failure or contamination. Causes excessive play, grinding noises, and eventual seizure.
Gear Wear/Failure: Caused by prolonged operation with contaminated oil or extreme overloading. Results in loss of power, metal chips in the oil, and catastrophic failure.
Sprocket Wear: The teeth can become pointed, hooked, or broken. While the sprocket itself is replaceable, severe wear often indicates the entire final drive has been under stress.
B. Maintenance & Inspection:
Daily: Walk-around inspection for any signs of oil leaks around the final drive.
Regular (Every 500-1000 hours): Check the gear oil level via the inspection plug. The oil should be clean and at the correct level. Change the oil per the manufacturer's strict interval (e.g., every 1000 hours is common).
Listen: Unusual grinding, whining, or knocking sounds from the final drive during operation are early warning signs of internal failure.
5. Sourcing and Procurement Options
Genuine SANY (OEM):
Source: Directly from an authorized SANY dealer.
Advantage: Guaranteed perfect fit, performance, and full warranty. The safest choice.
Consideration: Highest cost.
Premium Quality Remanufactured:
Source: Specialist rebuilders who use OEM-quality seals and bearings.
Advantage: Significantly lower cost than new OEM, often with a good warranty. A very popular and cost-effective option for a core component like this.
Consideration: Quality can vary between rebuilders. Choose a reputable company.
Aftermarket/New (Will-Fit):
Source: Companies that manufacture new, compatible final drives.
Advantage: New unit, often at a price between OEM and remanufactured.
Consideration: Must be meticulously cross-referenced for compatibility. Reliability should be vetted through reviews.
Exchange/Core Charge:
Most sellers, including SANY dealers, will charge a core charge (a refundable deposit) for the old, worn final drive. This core is then sent back to be remanufactured. Ensure your old unit is returnable to get the core refund.
6. Replacement Considerations
Replacing a final drive is a major repair. Key considerations include:
Diagnosis: Ensure the problem is truly the final drive and not the main hydraulic pump, control valve, or pilot system.
Side: Final drives are side-specific. The left and right final drives are mirror images of each other and are not interchangeable. You must order the correct side (Left/Port or Right/Starboard) for your machine.
Professional Installation: Highly recommended due to the weight, complexity, and critical torque specifications of the mounting bolts. Incorrect installation can lead to immediate failure.
Fluid and Filter Change: Always change the hydraulic oil and filters after a final drive failure, as metal debris likely contaminated the entire system.
