CY2 Series Hydraulic Rotary Actuators Principle Introduction

The CY2 series hydraulic rotary actuator transforms the linear motion of a piston into powerful flange rotational movement. Each actuator consists of an integrated ring gear (1) and only two moving parts: the central shaft (2) with an integrated bearing and mounting flange, and the annular piston sleeve (3).

Internal Design and Operation

The helical spline on the shaft engages with the internal helical grooves of the piston sleeve.

The external helical grooves of the piston sleeve engage with the integrated gear ring of the housing.

When hydraulic pressure drives the piston, it moves axially while simultaneously rotating, similar to the motion of a linear actuator. This action results in the rotation of the shaft. With the balance valve closed, hydraulic oil is trapped within the actuator, locking the shaft firmly in its rotational position.

The initial position of the piston and shaft is indicated by vertical lines, and arrows denote the direction of rotation. The housing's integrated gear ring remains stationary throughout the operation. For clarity, the shaft flange, wear-resistant guide rings, and end cap are not shown in the diagrams.

Key Features

Radial Load Support: The shaft is supported by wear-resistant guide rings (300, 301, and 302) to handle radial loads effectively.

Axial Load Isolation: Axial washers (304) separate the shaft from the housing, preventing axial load transfer.

Gap Adjustment: The end cap (4) adjusts axial clearances via set plugs (105) and pull-out pins (109).

Balance Valve Benefits

Many CY2 series hydraulic rotary actuators come equipped with factory-installed balance valves offering four key functions:

1. Overload Protection: Prevents damage to the actuator under excessive load.

2. Position Locking: Maintains the rotary angle when external loads are applied, eliminating position drift.

3. Reduced Hydraulic Kickback: Enhances system stability by minimizing pressure surges.

4. Controlled Speed: Ensures consistent rotation speed under eccentric loads.

Working Principle

Hydraulic oil pushes the piston axially, and the helical gear design causes the piston and shaft to rotate simultaneously. The dual-helical design results in compound rotation, with the shaft rotating approximately twice as much as the piston. Reversing the hydraulic flow through the opposite port returns the piston and shaft to their initial positions.

The CY2 series includes multiple models, all sharing the same internal design but varying in dimensions to meet different application requirements.

Applications of Hydraulic Rotary Actuators

CY2 series hydraulic rotary actuators find applications in a variety of industries, including:

Construction Machinery: Driving bucket and boom rotation in excavators and loaders.

Mining Equipment: Ensuring precise control in drilling rigs and conveyor systems.

Industrial Automation: Providing rotational power for machining centers, milling machines, and industrial robots.

Conclusion

The CY2 series hydraulic rotary actuator is a versatile and robust solution for converting hydraulic energy into rotational motion. With integrated features like balance valves and a compact design, these actuators deliver reliable performance across demanding applications.

Changsha Chiyu Hydraulic Equipment Co., Ltd. specializes in the production of hydraulic rotary actuators. Contact us for high-quality replacements or new installations tailored to your equipment.