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24

2023

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04

Valve driven hydraulic actuator - spiral hydraulic actuator

Classification:


【Summary description】The spiral swing actuator is a special type of oil cylinder that utilizes a large angle of rise screw to achieve output swing, also known as a reciprocating oil cylinder. It is a double helix swing cylinder completely different from the traditional design concept of swing cylinders. Compared to traditional gear rack swing cylinders and blade swing motors, the double helix swing hydraulic actuator has the advantages of compact structure, safety and reliability, small space occupation, easy design, large output torque and swing angle, etc. Double spiral swing hydraulic actuators have been applied in almost every situation that requires high torque limited swing motion. Spiral actuators are generally divided into foot mounted and flange mounted styles.

Today, let's briefly talk about another structure of hydraulic actuator - spiral actuator.

A typical spiral actuator is shown in the following figure.

The spiral swing actuator is a special type of oil cylinder that utilizes a large angle of rise screw to achieve output swing, also known as a reciprocating oil cylinder. It is a double helix swing cylinder completely different from the traditional design concept of swing cylinders. Compared to traditional gear rack swing cylinders and blade swing motors, the double helix swing hydraulic actuator has the advantages of compact structure, safety and reliability, small space occupation, easy design, large output torque and swing angle, etc. Double spiral swing hydraulic actuators have been applied in almost every situation that requires high torque limited swing motion. Spiral actuators are generally divided into foot mounted and flange mounted styles.

The typical structure of a spiral actuator is that the outer surface of the piston is matched with a set of spiral teeth on the surface of the cylinder body; The spiral teeth machined on the inner surface of the piston mesh with the spiral teeth on the output shaft. As shown in the following figure.

The inner gear of the piston and the outer gear of the output shaft form the first stage spiral pair, while the outer gear of the piston and the inner gear of the fixed ring form the second stage spiral pair. Under the action of axial hydraulic pressure, the piston moves back and forth in the cylinder body, achieving forward and reverse rotation of the output shaft of the spiral tooth swinging hydraulic cylinder through the meshing effect of the two-stage spiral pairs, thereby outputting a certain angle and torque.

The transmission efficiency of the single-stage screw pair of the double screw swing cylinder is only about 80%. When the efficiency of the two-stage screw pair is multiplied, the mechanical efficiency of the actuator is lower, generally about 64% - 75%. Compared to single stage gear rack transmission, the efficiency is lower.

There are many types of spiral tooth swing hydraulic cylinders studied abroad, and most of them have been mass-produced and put into use. Their manufacturers mainly include Helac Company in the United States, Scana Skarpenord AS Company in Norway, TAKEDA Company in Japan, and HKS Company in Germany. Among them, the series of swing hydraulic cylinders produced by HKS Company have a maximum output torque of 250 kN · m and a positioning accuracy of 0 3 °, with a standard return angle of up to 1000 °.

The design working pressure of the spiral swing cylinder is higher than that of the gear rack cylinder. Most manufacturers design a working pressure of 210Bar, and the gear rack swing cylinder is usually designed with a maximum working pressure of 150Bar.

The main motion of the spiral actuator motion pair is rotary motion, and the sealing components involved need to be selected that are suitable for rotary motion and high pressure. The main motion of the gear and rack actuator is linear motion, and the selected sealing components are mainly linear motion.