KOBELCO SK330-10/SK380-10 Track Bottom Roller Assy Heavy duty excavator undercarriage components factory&Source manufacture

Kobelco SK330-10/SK380-10 Track Bottom Roller Assembly exemplifies Japanese engineering precision and durability. Its robust construction, featuring a forged and induction-hardened shell, heavy-duty bearing system, and advanced multi-stage sealing technology, is designed to deliver reliable performance and an extended service life in the most demanding applications. As a fundamental load-bearing point, its condition is a direct barometer of overall undercarriage health and is a critical factor in the machine’s productivity, stability, and long-term operating economics.

Professional Technical Description: Kobelco SK380-10 Track Bottom Roller Assembly

1. Product Overview and Primary Function

The Kobelco SK380-10 Track Bottom Roller Assembly is a quintessential load-bearing component within the undercarriage system of the Kobelco SK380-10 hydraulic excavator. Positioned along the lower track frame between the front idler and the drive sprocket, its primary function is to support the dynamic and static weight of the machine and to guide the track chain along its designated path. These rollers are the primary contact points that transfer the machine’s operational load to the ground through the track chain, while simultaneously ensuring smooth travel, maintaining precise alignment, and absorbing ground-level shocks and impacts. Their performance is intrinsically linked to machine stability, traction, fuel efficiency, and the overall service life of the undercarriage system.

2. Key Functional Roles

• Primary Load Bearing: Supports the immense weight of the excavator during all operational phases, including digging, lifting, swinging, and traveling. They are subjected to extreme radial loads and shock impacts.
• Track Guidance and Containment: The double-flanged design is engineered to guide the track chain, maintaining perfect alignment on the roller path and preventing lateral derailment, which is critical during turns and operation on sloped or uneven terrain.
• Vibration and Impact Dampening: Absorbs and dissipates kinetic energy from traversing rough terrain, rocks, and other obstacles. This protects the track frame and the mainframe from excessive stress, reducing structural fatigue.
• Smooth Propulsion: Provides a continuous, rotating, hardened surface for the track chain bushings to ride on, minimizing rolling resistance and ensuring efficient power transmission from the final drive to the ground.

3. Detailed Component Breakdown & Construction

The Bottom Roller Assembly for a machine in the 40-ton class like the SK380-10 is a robust, sealed, and maintenance-free unit designed for maximum durability. Key sub-components include:

• Roller Shell (Body): The main cylindrical body that interfaces directly with the track chain bushings. It is typically manufactured from high-carbon, high-tensile alloy steel. The outer running surface is precision-machined and undergoes induction hardening to achieve a profound surface hardness (typically 58-62 HRC) for exceptional resistance to abrasive wear. The core of the shell remains ductile to withstand high-impact loads without catastrophic failure.
• Integral Flanges: Massive, double flanges are integral to the roller shell. These are critical for containing the track chain and preventing derailment. The inside surfaces of these flanges are also hardened to resist wear from constant lateral contact with the track links.
• Shaft (Spindle or Journal): A stationary, hardened, precision-ground, and high-tensile steel shaft. It is the structural anchor of the assembly, bolted directly to the track frame. The entire roller assembly rotates around this stationary shaft via the bearing system.
• Bearing System: Utilizes two large, heavy-duty tapered roller bearings pressed into each end of the roller shell. These bearings are specifically selected and pre-loaded to handle the extreme radial and axial loads generated by the machine’s weight and dynamic operational forces.
• Sealing System: This is the most critical subsystem for longevity. Kobelco employs an advanced, multi-stage, positive-action sealing system, which is likely to include:
  • Primary Multi-Lip Seal: A spring-loaded, nitrile rubber seal that provides the main barrier for retaining lubricating grease within the bearing cavity.
  • Secondary Dust Lip / Labyrinth Seal: An outer barrier designed to actively exclude abrasive contaminants (e.g., silica dust, slurry, mud) from reaching the primary seal.
  • Metal Seal Case: Provides a rigid, press-fit housing for the seals, ensuring they remain seated and effective under extreme vibration and load.
    These assemblies are Lube-for-Life, meaning they are sealed, pre-lubricated with high-temperature grease at the factory, and require no routine maintenance, thereby eliminating a potential point of contaminant ingress.
• Mounting Bosses: The forged or fabricated lugs integrated at each end of the shaft. They provide the bolting interface to securely attach the entire assembly to the excavator’s track frame with high-strength bolts.

4. Material and Manufacturing Specifications

• Material: The roller shell and shaft are constructed from high-grade, heat-treated alloy steels (e.g., equivalent to SCM440 or similar chrome-molybdenum steel), chosen for their superior strength, hardenability, and impact resistance.
• Manufacturing Processes: The process involves forging the shell for a superior continuous grain structure, precision CNC machining of all critical dimensions, induction hardening of all wear surfaces, fine grinding, and automated, press-fit assembly of bearings and seals in a controlled, clean environment.
• Surface Treatment: The assembly is shot-blasted to clean and improve paint adhesion before being coated with a corrosion-resistant primer and Kobelco’s signature blue paint finish.

5. Application and Compatibility

This assembly is specifically engineered for the Kobelco SK380-10 excavator. Bottom rollers are consumable wear items due to their constant ground contact and exposure to abrasives. They are typically inspected regularly and replaced in sets to ensure even support, balanced load distribution, and consistent performance across the entire undercarriage. Using the correct OEM-specified part is crucial for maintaining proper track shoe height, alignment, and overall machine performance and safety.

6. Importance of Genuine or Premium-Quality Parts

Using a Genuine Kobelco or a certified high-quality equivalent assembly ensures:

• Precision Engineering: Exact conformance to OEM dimensions and tolerances, guaranteeing perfect fitment with the track chain and correct alignment on the track frame.
• Material Integrity: Certified materials and precise heat treatment ensure the roller meets its designed service life, resisting abrasive wear, spalling, and impact fractures.
• Seal Reliability: The quality of the sealing system is the primary determinant of roller life. Premium Kobelco-grade seals prevent the leading cause of failure: lubricant loss and contaminant ingress, which lead to premature bearing seizure.
• Balanced Undercarriage Wear: Promotes even wear across all undercarriage components (rollers, idlers, track chain, sprocket), protecting the larger investment and optimizing total cost of ownership.

7. Maintenance and Operational Considerations

• Regular Inspection: A daily walk-around inspection should include:
  • Rotation: Ensure all rollers turn freely. A seized (non-rotating) roller will be worn flat and will act as a brake, causing accelerated, catastrophic wear to itself and the track chain links.
  • Flange Wear: Check for excessive wear or damage to the guiding flanges.
  • Leakage: Look for any signs of grease leaking from the seal area, which is a clear indicator of seal failure and impending bearing failure.
  • Visual Damage: Inspect for cracks, deep gouges, or significant scoring on the roller shell.
• Cleanliness: While designed for harsh conditions, operating in environments with material that packs solidly around the rollers (e.g., clay) can increase stress and act as an abrasive paste, accelerating wear. Periodic cleaning is beneficial.
• Proper Track Tension: Always maintain track tension according to the manufacturer’s specifications outlined in the operator’s manual. Incorrect tension is a primary cause of accelerated and uneven undercarriage wear.

CQC TRACK also can manufacturer the  Kobelco undercarriage aftermarket parts SK380 undercarriage below:

1. Kobelco SK380 track assembly 53L 600MM  Kobelco SK380 track shoes assy
2. Kobelco SK380 track shoes 600MM  SK380 track plates SK380 steel track pads
3. Kobelco SK380 track chains Kobelco SK380 track links assy
4. Kobelco SK380 Track bolts and nuts
5. Kobelco SK380 lower rollers SK380 bottom rollers, SK380 track rollers
6. Kobelco SK380 front idlers
7. Kobelco SK380 idlers bolts
8. Kobelco SK380 sprocket
9. Kobelco SK380 sprocket bolts
10. Kobelco SK380 top rollers  SK380 carrier rollers, SK380 upper rollers
11. Kobelco SK380 Carrier rollers bolts