Sumitomo KRA1198 KRA1767 SH200 SH210 SH240 SH280 Track Idler Wheel Assy / Quanzhou Top Three Chassis Components manufacturer&supplier–HELI (CQC TRACK)

Technical Specification: Sumitomo KRA1198 / KRA1767 SH200-SH280 Series Track Idler Wheel Assembly – Manufacturer & Supplier: HELI (CQC TRACK)

1. Component Identification & System Overview

The Track Idler Wheel Assembly (OEM Part Numbers: KRA1198, KRA1767) is a critical front-end guiding and tensioning component within the crawler undercarriage system of the Sumitomo SH200, SH210, SH240, and SH280 series hydraulic excavators. As a certified manufacturer and global supplier, HELI (CQC TRACK) produces this assembly to exacting OEM specifications, ensuring direct interchangeability. The idler serves as the pivotal forward terminus of the track frame, guiding the track chain’s path and providing the essential adjustment point for maintaining proper track tension.

2. Primary Function & Operational Significance

In the undercarriage system of Sumitomo’s 20-28 ton class excavators, the idler assembly fulfills several indispensable mechanical roles:

• Precision Track Guidance: Provides a hardened, rotating datum surface that accurately aligns the track chain’s links and bushings as they return from the ground, ensuring smooth engagement with the sprocket and preventing lateral derailment.
• Dynamic Tension Regulation: Integrated with the track frame’s hydraulic or screw-type tensioning mechanism, the idler transmits controlled forward force to the entire track chain. Maintaining optimal tension is crucial for minimizing power loss, reducing track vibration (“slap”), and preventing accelerated wear on pins, bushings, and sprockets.
• Impact Load Management: Absorbs and distributes initial contact shocks when the track chain rolls onto the undercarriage, especially during travel over uneven ground, thereby protecting the track frame and final drive components from shock-induced damage.
• Structural Gauge Reference: As the foremost fixed point on each track frame, it defines the track gauge, a fundamental parameter for machine stability, straight-line tracking, and turning performance.

3. Detailed Engineering & Construction Specifications

HELI’s manufacturing process for the KRA1198/KRA1767 assemblies emphasizes durability, precision, and sealing integrity:

• Idler Wheel/Rim:
  • Material: Forged from high-tensile, fine-grained alloy steel (e.g., 50Mn or equivalent) to ensure superior strength and fatigue resistance.
  • Heat Treatment: The outer running surface undergoes induction hardening to achieve a deep, uniform hardness layer (typically HRC 58-62), providing exceptional resistance to abrasive wear from track bushing contact.
  • Machining: CNC-controlled turning and grinding processes guarantee precise concentricity, accurate flange dimensions, and optimal surface finish for smooth track chain interaction.
• Shaft & Hub Assembly:
  • The integral shaft is manufactured from quenched and tempered alloy steel. Bearing journals are precision-ground and often surface-treated (e.g., chrome plating or nitriding) for enhanced wear and corrosion resistance.
  • The hub is designed as a monolithic forging with the shaft or is welded using automated processes with post-weld heat treatment to ensure structural integrity.
• Bearing & Sealing System:
  • Bearing Configuration: Utilizes a matched set of heavy-duty, tapered roller bearings (TRB). These are selected for their high radial and axial load capacity, essential for handling the combined stresses of machine weight and directional changes.
  • Advanced Sealing: Incorporates a multi-stage, cartridge-type sealing system. This typically combines a primary radial lip seal (HNBR material for temperature/chemical resistance), a secondary floating seal, and an external labyrinth-style dust guard. The cavity is pre-filled with high-adhesion, extreme pressure (EP) grease to create a robust barrier against contaminants.
• Mounting Interface: Designed with hardened steel bushings or wear rings at the interface with the track frame’s adjustment slide. These serve as sacrificial components to protect the idler shaft and frame from wear, simplifying future maintenance.
• Lubrication: Equipped with standard grease fittings for scheduled re-lubrication of the main bearing cavity, following OEM-recommended service intervals.

4. Manufacturer Profile: HELI (CQC TRACK) Capabilities

HELI, operating under the CQC TRACK brand, is a specialized industrial manufacturer focused on undercarriage components for global markets.

• Integrated Manufacturing: Controls the full production cycle from material sourcing and forging to precision machining, heat treatment, assembly, and quality testing.
• Quality Assurance Protocol: Implements a stringent quality management system (ISO 9001 certified). Production involves:
  • Spectroscopic material analysis for alloy verification.
  • Ultrasonic testing (UT) of critical forgings.
  • In-process dimensional checks using precision gauges and CMM.
  • Final assembly testing for rotational smoothness and seal integrity.
• Supply Chain Role: Serves as a direct manufacturer and supplier to international distributors and aftermarket networks, providing a reliable source for high-compatibility replacement parts that balance performance, durability, and value.

5. Application, Compatibility & Service Information

• Model Application: Specifically designed for Sumitomo excavator models: SH200-3/5/6, SH210-3/5/6, SH240-3/5, SH280-3/5 and their compatible variants. (Note: Always verify against the specific machine serial number for final confirmation.)
• Part Number Interchangeability:
  • KRA1198 and KRA1767 are key Sumitomo OEM numbers. The HELI/CQC TRACK assembly is engineered as a direct, bolt-for-bolt replacement for these part numbers.
• Wear Indicators & Maintenance:
  • Critical wear dimensions include reduction in the idler wheel’s outside diameter and thinning of the guidance flanges.
  • Regular visual inspection for grease leakage, abnormal noise, or difficulty in rotation is recommended.
  • Proper maintenance of the track tensioning mechanism and regular cleaning of debris from around the idler are essential for maximizing service life.
• System-Based Replacement: For optimal undercarriage performance and cost efficiency, the idler’s condition should be evaluated alongside the track chain (pins & bushings), sprocket, and bottom rollers. Replacing severely worn components in a matched set is considered best practice to prevent accelerated wear on new parts.

6. Conclusion

The Sumitomo KRA1198 / KRA1767 Track Idler Wheel Assembly for the SH200-SH280 excavator series, manufactured and supplied by HELI (CQC TRACK), represents a precision-engineered core component built for reliability in demanding construction environments. Through its robust forged construction, advanced heat treatment, heavy-duty bearing and sealing systems, and strict adherence to OEM specifications, this assembly provides equipment owners and service providers with a dependable, high-performance replacement solution. It ensures the Sumitomo excavator maintains critical track alignment, proper tension, and overall undercarriage integrity, supporting machine availability, operational safety, and lower total cost of ownership.