Rotary Actuators for Wrist Assembly | Specifications & Verification

Product Specifications

Technical details and manufacturing context for Rotary Actuators

Definition

Rotary actuators are precision components within the Wrist Assembly that provide controlled rotational movement, enabling the wrist's articulation and positioning capabilities. They serve as the primary motion source for wrist rotation in robotic and automation applications. These actuators convert hydraulic, pneumatic, or electrical energy into torque through mechanisms such as gear trains, vane systems, or ball screw assemblies, producing precise angular displacement for wrist movement control. Typical specifications include a torque range of 10–500 N·m, operating pressure of 0.4–0.8 MPa, rotation angle of 0–90 degrees, positioning accuracy of ±0.5 degrees, supply voltage of 24 V DC ±10% for electric versions, operating temperature of -20 to 80 °C, protection class IP65–IP67 (IEC 60529), body material of 304 stainless steel (ASTM A276), and weight of 2–15 kg. Materials commonly used include stainless steel, aluminum alloy, and engineering plastics. These values are reference ranges and must be verified for the specific model and application. Always confirm model-specific parameters and standards with the legal manufacturer or supplier before procurement or installation.

Working Principle

Rotary actuators convert hydraulic, pneumatic, or electrical energy into torque through mechanisms like gear trains, vane systems, or ball screw assemblies. This torque produces precise angular displacement, enabling controlled rotation for wrist movement. The actuator's output torque and rotation angle are determined by the input energy and internal mechanism design. For pneumatic or hydraulic types, operating pressure directly influences output torque; below 0.4 MPa, torque drops significantly. Electric versions rely on supply voltage, typically 24 V DC ±10%. Positioning accuracy depends on the actuator's internal feedback and control system; higher accuracy requires feedback control. The rotation angle is typically 0–90 degrees for quarter-turn applications, but custom angles are available. Operating temperature range affects seal integrity; outside -20 to 80 °C, seals may fail. Protection class indicates suitability for environments like washdown; IP67 is recommended for such conditions.

Common Materials

Stainless Steel, Aluminum Alloy, Engineering Plastics

Technical Parameters

Parameter	Typical range	Notes & selection driver
Torque	10–500 N·m	Select based on load and safety factor.
Operating Pressure	0.4–0.8 MPa	Below 0.4 MPa output torque drops significantly.
Rotation Angle	0–90 °	Typical for quarter-turn valves; custom angles available.
Positioning Accuracy	±0.5 °	Higher accuracy requires feedback control.
Supply Voltage	24 ±10% V DC	For electric actuators; pneumatic uses air pressure.
Operating Temperature	-20–80 °C	Seals may fail outside this range.
Protection Class	IP65–IP67	IP67 for washdown environments.IEC 60529
Body Material	304	Stainless steel for corrosion resistance.ASTM A276
Weight	2–15 kg	Depends on torque and options.

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

Housing Part
Protects internal components and provides structural support

Material: Aluminum Alloy
Output Shaft Part
Transmits rotational torque to the wrist assembly

Material: Stainless Steel
Seals Part
Prevents fluid leakage and contamination in hydraulic/pneumatic actuators

Material: Synthetic Rubber
Gear Train Optional
Turns the drive input into shaft torque on geared builds.
Vane System Optional
Takes the fluid pressure directly and swings the shaft on vane-type builds.
Ball Screw Optional
Converts a linear push into rotation on ball-screw builds.

Application & selection

Application Fit & Sizing Matrix

Operational Limits

speed:	Up to 100 rpm
pressure:	Up to 300 bar
temperature:	-40°C to 120°C
torque range:	10 Nm to 5000 Nm
rotation angle:	0° to 360° (continuous) or 90°/180° (quarter/half-turn)

Media Compatibility

✓ Hydraulic oil ✓ Industrial lubricants ✓ Clean dry air

Unsuitable: Abrasive slurry environments

Sizing Data Required

Required torque (Nm)
Rotation angle (degrees)
Operating pressure (bar)

Risk, maintenance & compliance

Reliability & Engineering Risk Analysis

Failure Mode & Root Cause

Seal degradation

Cause: Exposure to incompatible fluids, high temperatures, or particulate contamination leading to hardening, cracking, or extrusion of seals, resulting in internal or external leakage.

Bearing wear or failure

Cause: Inadequate lubrication, misalignment, excessive side loads, or ingress of contaminants causing increased friction, scoring, pitting, or seizure of bearing surfaces.

Maintenance Indicators

Audible grinding, clicking, or knocking noises during operation indicating internal mechanical interference or bearing damage.
Visible external fluid leakage around shaft seals or housing joints, often accompanied by reduced torque output or erratic movement.

Engineering Tips

Implement condition-based monitoring with vibration analysis and periodic oil sampling to detect early-stage bearing wear and fluid contamination before catastrophic failure.
Ensure proper alignment during installation and use flexible couplings where applicable to minimize side loads and torsional stresses on bearings and seals.

Indicative industry ranges for design and RFQ preparation. Confirm the exact figures and applicable standard with the manufacturer before specifying.

Compliance & Manufacturing Standards

Applicable Standards

ISO 5211:2017 - Mounting of industrial valves ANSI/B93.5M-1991 - Hydraulic fluid power - Rotary actuators DIN ISO 5211:2017-12 - Mounting of industrial valves

Quoted from the published standard.

Manufacturing Precision

Bore diameter: +/-0.025 mm
Flatness of mounting surfaces: 0.05 mm

Quality Inspection

Pressure testing for leakage (hydrostatic/pneumatic)
Torque output verification at specified pressure

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.

Compare the published product scope and source details, then include your specifications and quantity in an enquiry.

Manufacturers of Rotary Actuators

8 companies list this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

Flutec Hydraulics

Wuxi, Jiangsu, CN

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