Circle: Load Capacity 15-30 tons, Diameter 1200-1800 mm

Component Specifications

Definition

The circle in a motor grader is a precisely machined circular component that serves as the mounting platform for the moldboard blade. It rotates on a vertical axis to adjust blade angle, enabling precise grading, sloping, and material distribution. This component transfers hydraulic power into controlled rotational movement while maintaining structural integrity under heavy loads.

Working Principle

The circle operates through a hydraulic motor-driven gear mechanism that engages with teeth on its circumference. Hydraulic pressure creates rotational torque, allowing the circle to turn the attached blade to desired angles (typically 0-90°). Precision bearings support the circle's rotation while maintaining alignment with the grader frame.

Materials

High-strength alloy steel (ASTM A572 Grade 50 or equivalent), heat-treated to 35-40 HRC hardness, with corrosion-resistant coating (zinc plating or powder coating).

Technical Parameters

Parameter	Typical range	Notes & selection driver
Weight	150-300 kg
Diameter	1200-1800 mm
Thickness	25-40 mm
Gear Teeth	120-180 teeth
Load Capacity	15-30 tons
Rotation Speed	2-5 RPM
Operating Pressure	150-250 bar

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

Standards

ISO 8525, DIN 15061, SAE J1179

Parent Products

This component is used in the following industrial products

Motor Grader

A heavy-duty construction machine with a long blade used to create flat surfaces.

View Product Details

Engineering Analysis

Risks & Mitigation

Gear tooth wear leading to imprecise blade positioning
Structural fatigue cracks from cyclic loading
Bearing failure causing rotation instability
Corrosion in harsh environments

FMEA Triads

Trigger: Inadequate lubrication
Failure: Increased friction and premature gear wear
Mitigation: Implement automated lubrication systems with pressure monitoring

Trigger: Overloading beyond design capacity
Failure: Structural deformation or cracking
Mitigation: Install load sensors with automatic operation limits

Trigger: Environmental contamination
Failure: Bearing seizure and rotation failure
Mitigation: Use sealed bearing assemblies with regular cleaning protocols

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.5 mm diameter tolerance, ±0.1° angular positioning accuracy

Test Method

Dimensional verification with laser scanning, load testing at 150% rated capacity, rotational accuracy testing with theodolite measurement

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Circle

Manufacturer profiles associated with Circle.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

Related Components

Upper Tool (Punch)

Upper Tool (Punch) is the active forming component in metal plate bending machines that applies precise downward force to create bends in sheet metal.

Main Frame

The main frame is the primary structural component of a hydraulic press, providing rigidity and stability to withstand high compressive forces during metal forming operations.

Shaft Bearing

Precision component supporting rotating shafts in vibration motors to reduce friction and maintain alignment.

Seal Groove

Precision-machined groove in aluminum bearing housings designed to accommodate sealing elements for fluid containment and contamination prevention.

Frequently Asked Questions

What is the primary function of the circle in a motor grader?

The circle provides rotational movement to the moldboard blade, allowing operators to adjust cutting angles for precise grading operations.

How often should the circle be inspected?

Perform visual inspections every 250 operating hours and complete dimensional checks every 1000 hours to ensure gear tooth integrity and proper lubrication.

Can circles be repaired or must they be replaced?

Minor gear tooth damage can be repaired through welding and machining, but severe wear or structural cracks requires complete replacement.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Circle