Hydraulic Axis for Precise Motion Control

Hydraulic linear cylinders perform axial movement. This can be controlled in various ways. A hydraulic axis allows for particularly precise motion control of the hydraulic cylinder.

Controlling Hydraulic Cylinders with a Hydraulic Axis

The simplest configuration for linear motion is the single-acting cylinder. In this setup, hydraulic oil is simply pumped into the cylinder until the piston is fully extended. Stopping is only possible manually by observing the piston during extension and switching off the pump in time. Retraction is only possible by relieving pressure from the cylinder. Neither stroke, speed, nor pulling force can be controlled in this manner.

In double-acting cylinders, the retraction force equals the extension force. This already adds a dimension of adjustability to the linear cylinder.

A hydraulic axis offers convenient control of a linear cylinder. This refers to an assembly that, while having the hydraulic linear motor as its core, only achieves its desired function through several attached components.

Components of a Hydraulic Axis

A hydraulic axis consists of the following components:

• Hydraulic cylinder
• Return line for double action
• Sensors
• Control electronics

The sensors monitor the piston’s position throughout the entire stroke. With their help, the control electronics always know exactly how far the piston has extended from the hydraulic cylinder. This allows for precise calculation of the extension distance, extension speed, and applied force.

Advantages of the Hydraulic Axis

The controlled movement primarily serves to keep the piston controllable throughout the entire extension stroke. Precisely targeting a defined point makes it independent of the cylinder’s size. This enables designs that can accommodate multiple working paths along a linear section.

Since the extension speed and force can also be regulated with a hydraulic axis, further configurations are possible. Where fast movements are required, the system’s operational efficiency can be increased. For movements not subject to force, pressure can be reduced, saving drive energy and protecting the mechanics.

Application of the Hydraulic Axis

The hydraulic linear axis is particularly well-suited for automated or semi-automated systems. The controlled configuration helps prevent operating errors and keeps the movement consistently within its intended range. Hydraulic linear axes are therefore frequently found in construction vehicles of all types.

The Difference to Hydraulic Rotary Axes

Some manufacturers also refer to their adjustable rotary motors as hydraulic axes. This is not entirely technically precise but has become common in technical jargon. These are rotating drive components. They do not regulate the extension stroke but rather an applied torque. Hydraulic rotary axes are, for example, widely used in agriculture for driven trailer axles.