Hitachi 135 UR Hydraulic Excavator Overview

[MikePhua]

Model Background
The Hitachi 135 UR is a mid-sized hydraulic excavator from the late 1990s and early 2000s renowned for its underground utility and urban excavation capabilities due to its reduced tail swing radius. This model balances compact dimensions with strong digging power and advanced hydraulics typical for its era.
Specifications

• Engine: Typically powered by a reliable Isuzu or Mitsubishi diesel engine producing about 93 horsepower (69 kW).
  
• Operating Weight: Approximately 14,000 to 15,400 kg (31,000 to 34,000 lbs), depending on configurations and attachments.
  
• Hydraulic System: Features dual variable-displacement axial piston pumps delivering roughly 117 liters per minute of oil flow.
  
• Operating Pressure: Relief valve set around 34.3 MPa (approximately 350 bar or 5,000 psi) ensuring ample force for digging and lifting.
  
• Bucket Capacity: Varies with hydraulic attachments, often around 0.5 to 0.6 cubic meters; excellent for narrow trenching and precise excavation.
  
• Boom Configurations: Offers mono or two-piece boom options with reach lengths ranging between 7.3 m to 8.85 m.
  
• Swing Radius: Compact rear-end swing radius of around 1.48 meters allows work in congested spaces.
  
• Undercarriage: Robust tractor-style undercarriage fitted with triple grouser shoes spanning 500 to 700 mm widths, for enhancing ground contact and traction.
  
• Fuel and Fluid Capacities: Fuel tanks commonly around 220 liters, hydraulic oil approximately 165 liters.
  
• Operator Comfort: Spacious cab featuring reinforced glass on all sides with reclining adjustable seats and advanced controls for operator ease.
  

Performance Highlights

• Excellent boom and arm digging forces ranking over 70 kN on the arm and up to 99 kN on the bucket, suited for heavy-duty earthmoving.
  
• Hydraulic cylinders designed with cushion mechanisms to absorb shocks and ensure smooth operation.
  
• Swing motor is an axial piston motor with planetary reduction, providing a swing speed around 13.7 rpm.
  
• Travel functions use dual variable displacement motors for efficient maneuverability at speeds up to 3.4 km/h to 5.6 km/h.
  

Design and Utility

• The model’s reduced tail swing (UR) makes it suitable for urban and underground work where space is limited.
  
• Equipped with modern hydraulic filtration systems providing clean oil to the hydraulic circuits, which include safety features such as hose rupture valves.
  
• Versatile with different arm lengths and buckets, supporting restoration, pipeline, and landscaping projects.
  

Terminology

• Variable Displacement Pump: A hydraulic pump that adjusts oil flow depending on demand and load.
  
• Triple Grouser Shoes: Track shoes with three protrusions for better grip on loose or uneven terrain.
  
• Axial Piston Motor: Hydraulic motor type used for high torque and efficient rotary power.
  
• Boom Cushion: Hydraulic cylinder feature that dampens shock at end of stroke.
  
• Tail Swing Radius: The distance from the pivot point to the rear extremity of the excavator’s upper structure, critical for confined space work.
  

Real-World Usage
Operators highlight the Hitachi 135 UR for its excellent blend of strength and compactness, which makes it ideal for urban construction sites with limited maneuvering space. Its smooth hydraulic operation and robust build provide high productivity while enhancing operator safety.
Conclusion
The Hitachi 135 UR hydraulic excavator reflects the industry’s move toward compact, powerful, and operator-friendly machines. Its technical features, including a strong hydraulic system, efficient engine, reduced swing radius, and ergonomic cab, make it a sound investment for versatile earthmoving tasks in constrained environments.