Types of Rotary Hydraulic Cylinders
1. Vane-Type Rotary Hydraulic Cylinder
A vane-type rotary hydraulic cylinder generates rotation by using pressurized hydraulic oil to drive internal vanes connected to the output shaft.
• The rotation angle is typically less than 360°, commonly 90° or 180°
• Features a compact structure, light weight, and fast response
• Well suited for applications requiring high-frequency, small-angle rotation
2. Piston-Type Rotary Hydraulic Cylinder
A piston-type rotary hydraulic cylinder converts the linear motion of a piston into rotary motion through mechanisms such as rack-and-pinion or screw-and-nut assemblies.
• Supports a wide rotation angle, including over 360° and multi-turn rotation
• Provides higher output torque, making it suitable for heavy-duty applications
Typical Applications
Rotary hydraulic cylinders are widely used in applications that require controlled angular movement, including:
• Construction machinery (e.g. excavator bucket swing)
• Metallurgical equipment
• Marine deck machinery
• Industrial clamps and grippers (opening and closing actions)
These actuators play a critical role in improving motion precision, load capacity, and automation efficiency.
Structural Comparison: Vane-Type vs. Piston-Type Rotary Hydraulic Cylinders
| Comparison Criteria | Vane-Type Rotary Hydraulic Cylinder | Piston-Type Rotary Hydraulic Cylinder |
| Core Transmission Structure | Cylinder housing, stator, vanes, output shaft | Piston + rack & pinion or screw-nut mechanism + output shaft |
| Rotation Angle | Typically < 360° | Wide angle range, can exceed |
| Range | fixed angles such as 90° or 180° | 360°; some designs allow multi-turn rotation |
| Output Torque Characteristics | Relatively lower torque, smooth output | High torque, suitable for heavy-load conditions |
| Size & Weight | Compact design, small size, lightweight | More complex structure, larger size and heavier weight |
| Response Speed | Direct oil-driven vanes, fast response | Mechanical conversion involved a slightly slower response |
| Sealing Requirements | Higher sealing difficulty on both sides of vanes | Mainly piston sealing, relatively easier to manage |
