Upper Structure (House) for Hydraulic Excavators

Product Specifications

Technical details and manufacturing context for Upper Structure (House)

Definition

The upper structure, also known as the house or revolving frame, is the rotating component of a hydraulic excavator mounted on the undercarriage. It contains the operator's cab with controls, the engine and power system, hydraulic pumps and tanks, counterweight, and all major working components. This structure rotates 360 degrees on the swing bearing, allowing the excavator to dig and dump material without moving the tracks. The upper structure is typically fabricated from high-strength steel and structural steel plate, providing the rigidity needed to support the excavator arm and attachments during heavy digging operations. It houses critical systems such as the hydraulic pumps that supply flow to the boom, arm, bucket, and swing motors, as well as the engine that provides power. The counterweight at the rear balances the machine during lifting and digging. The swing bearing connects the upper structure to the undercarriage, enabling smooth rotation. The upper structure also includes the operator's cab, which is designed for visibility and comfort, with controls for all machine functions. The design of the upper structure must account for the distribution of weight, the routing of hydraulic lines and electrical cables, and the protection of components from environmental factors. The swing speed, swing torque, operating pressure, hydraulic flow rate, engine power, operating temperature, IP rating, material grade, weight, and footprint are key parameters that define the performance and compatibility of the upper structure with different excavator models. These values are provided as reference ranges and must be verified for the specific model and application. The upper structure is a critical component that determines the overall stability, efficiency, and safety of the excavator. Proper maintenance, including regular inspection of the swing bearing, hydraulic connections, and structural integrity, is essential to ensure reliable operation and prevent failures. When selecting or replacing an upper structure, it is important to consult the legal manufacturer or supplier to confirm that the specifications match the excavator's requirements and applicable standards.

Working Principle

The upper structure rotates on a swing bearing mounted to the undercarriage, powered by a hydraulic swing motor. This rotation enables the excavator arm and attachment to reach different positions while the machine remains stationary. The structure houses and protects all critical systems while providing a stable platform for excavation operations. The swing motor receives hydraulic fluid from the pumps, converting pressure into torque to rotate the upper structure. The swing bearing allows smooth 360-degree rotation, and the counterweight balances the load. The operator controls the swing speed and direction using the joysticks in the cab. The upper structure also supports the boom, arm, and bucket, which are actuated by hydraulic cylinders. The engine drives the hydraulic pumps, which supply flow to all circuits. The design ensures that the center of gravity remains within safe limits during operation.

Common Materials

High-strength steel, Structural steel plate

Technical Parameters

Parameter	Typical range	Notes & selection driver
Swing Speed	8–12 r/min	Higher speed reduces cycle time but increases inertial loads.
Swing Torque	50–200 kN·m	Must match excavator size class for adequate rotation force.
Hydraulic Flow Rate	150–300 L/min	Determines actuator speed and power availability.
Engine Power	100–300 kW	Net power at flywheel; must meet emission standards.ISO 9249
Operating Temperature	-20–50 °C	Outside this range, hydraulic fluid viscosity changes affect performance.
IP Rating	IP54–IP65	Protects electrical components from dust and water ingress.IEC 60529
Material Grade	Q345B–Q460C	Higher grade for increased strength and fatigue resistance.GB/T 1591
Weight	3000–8000 kg	Affects transport and crane lifting requirements.
Footprint (Length × Width)	2500–4000 × 2000–3000 mm	Must fit within excavator transport envelope.

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Operator's Cab
Enclosed compartment for the operator with controls, seat, and safety features

Material: Steel and safety glass
Engine Mounting Frame
Structural frame that supports and secures the engine and power system

Material: Structural steel
Hydraulic Pump Mounting Plate Part
Platform for mounting hydraulic pumps and associated components

Material: Steel plate
Counterweight Mounting Structure Part
Reinforced area for attaching counterweight to balance digging forces

Material: High-strength steel
Swing Bearing Mounting Ring Part
Circular mounting surface for the swing bearing that connects to undercarriage

Material: Machined steel
Counterweight
Balances digging and lifting loads at the rear of the platform.

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Hydraulic Excavator

View system integration details

Manufacturers of Upper Structure (House)

Manufacturer profiles associated with Upper Structure (House).

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Frequently Asked Questions

What is the function of the upper structure in a hydraulic excavator?

The upper structure is the rotating platform that houses the operator's cab, engine, hydraulic pumps, and other key components. It rotates 360 degrees on the swing bearing, allowing the excavator to dig and dump material without moving the tracks.

What materials are typically used for the upper structure?

The upper structure is typically fabricated from high-strength steel and structural steel plate, as listed in the directory. The material grade, such as Q345B to Q460C, affects strength and fatigue resistance and must be verified for the specific model.

What are the key parameters to consider when selecting an upper structure?

Key parameters include swing speed, swing torque, operating pressure, hydraulic flow rate, engine power, operating temperature, IP rating, material grade, weight, and footprint. These values are reference ranges and must be confirmed with the manufacturer for the actual model.

How should the upper structure be maintained?

Regular inspection of the swing bearing, hydraulic connections, and structural integrity is essential. Check for leaks, wear, and cracks. Follow the manufacturer's maintenance schedule and verify that all components meet the required standards.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records.

Preliminary Technical Classification

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pressure:	Hydraulic system: 350 bar max, structural: 1.5x design load safety factor
other spec:	Rotation speed: 0-12 RPM continuous, 15 RPM peak, Flow rate: 100-400 L/min hydraulic system, Vibration: ISO 2631-1 compliant for operator comfort
temperature:	-20°C to +50°C (operational), -40°C to +70°C (storage)

Upper Structure (House)

Product Specifications

Applied To / Applications

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