SIVIDI has developed a new draw-wire position sensor designed for external stroke measurement on hydraulic cylinders. The solution provides continuous position feedback by converting the linear movement of a hydraulic cylinder rod into a measurable position signal.
The development originated from a practical application involving hydraulic servo equipment, where the cylinder required reliable stroke monitoring without installing a position sensor inside the cylinder body.
In some hydraulic systems, integrating an internal displacement sensor is not always practical. Existing cylinder structures, retrofit projects, limited installation space, maintenance requirements, or non-standard mechanical designs may make an externally mounted solution more suitable.
To address this requirement, SIVIDI developed a draw-wire sensor configuration that can be mounted outside the hydraulic cylinder. The wire is mechanically linked to the moving part of the cylinder, allowing the sensor to follow the extension and retraction of the piston rod.
As the cylinder moves, the draw-wire mechanism converts the linear displacement into rotational motion inside the sensor. The internal position sensing element then generates a corresponding output signal for stroke measurement, position monitoring, or closed-loop control.
External Position Measurement Without Modifying the Cylinder
One of the main advantages of the external draw-wire design is that the hydraulic cylinder itself does not need to be internally modified.
This can be particularly useful for existing equipment, customized hydraulic cylinders, retrofit projects, and applications where internal sensor installation would increase mechanical complexity.
The sensor can be installed independently of the hydraulic circuit, making installation, adjustment, replacement, and maintenance more flexible.
For machine builders and hydraulic system integrators, this approach also provides another option when conventional internal position sensing methods are not suitable for the mechanical structure of the application.
Designed Around Hydraulic Cylinder Motion
Hydraulic cylinder applications place different demands on a draw-wire sensor compared with general-purpose linear position measurement.
Repeated extension and retraction, vibration, mechanical shock, mounting direction, cable alignment, and the relationship between the sensor and piston rod movement all need to be considered during system design.
For this project, SIVIDI optimized the draw-wire mechanism and installation arrangement according to the actual cylinder structure and movement path.
Special attention was given to the mounting position, wire outlet direction, retraction mechanism, mechanical connection, and effective measuring stroke to ensure that the sensor can follow the hydraulic cylinder movement reliably.
The external installation concept also provides flexibility for adapting the design to hydraulic cylinders with different stroke lengths, mounting arrangements, and mechanical structures.
Applications Beyond Hydraulic Cylinders
Although this sensor was developed around a hydraulic cylinder application, the same draw-wire position sensing principle can also be used in other industrial systems requiring long-stroke linear displacement measurement.
Potential applications include:
- Hydraulic servo systems
- Test and measurement equipment
- Industrial machinery
- Engineering machinery
- Linear motion systems
- Retrofit position feedback systems
For applications with different mechanical dimensions, measuring ranges, or signal requirements, the sensor configuration can be adapted according to the actual installation conditions.
Expanding SIVIDI Position Feedback Solutions
SIVIDI develops rotary encoders and industrial position sensing solutions for automation, motion control, and machine applications.
The development of this hydraulic cylinder draw-wire position sensor extends SIVIDI's position feedback capability from rotary measurement into long-stroke linear displacement applications.
By combining a draw-wire mechanism with position sensing technology, the new solution provides an alternative approach for hydraulic cylinder stroke measurement, especially in applications where external installation, mechanical flexibility, and customized integration are important.
SIVIDI
Email：sividi360@outlook.com
