Hydraulic axis integrates cylinder, manifold and position sensor

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Hydraulic axis integrates cylinder, manifold and position sensorParker Hannifin is launching the HMIX electro-hydraulic cylinder for OEMs and end users requiring a combination of speed, power and precision. The HMIX cylinder is a fully integrated sub-system that combines proven Parker tie-rod hydraulic cylinder, manifold, pipework and high-precision feedback transducer. This all-in-one, easy-to-fit unit enables machine builders to enhance the functionality and performance of machines quickly and simply, while reducing installation, configuration and maintenance times.

Key to the overall performance of the new HMIX electro-hydraulic cylinder is a sophisticated, internally mounted magnetostrictive transducer. This provides continuous analogue or digital feedback of the actuator's position, derived from the interaction of two magnetic fields. These are generated by a permanent magnet attached to the actuator piston and a magnetic pulse that is produced by a current pulse launched along a copper core inside a waveguide tube inside the piston rod. The interaction between the two fields produces a torsional strain pulse, which travels down the waveguide tube and is sensed by a coil at the end of the device. The position of the piston-mounted permanent magnet is established by measuring the elapsed time between the start of the current pulse and the arrival of the strain pulse, with interface electronics converting this information into a digital or analogue output.

This robust and reliable technology can be used under closed- or open-loop control. For the former, the transducer can provide accurate information of position, velocity or motion control over the full stroke of the cylinder, while in the latter mode the transducer acts as a continuous, infinite-resolution position monitoring device.

Easy integration

The compact design of the transducer means that the new HMIX electro-hydraulic cylinder is only slightly longer than a standard cylinder, thereby helping to simplify machine layouts. Similarly, the non-contacting design of the transducer, the tough steel protection tube for the transducer electronics and connector, plus the use of high-tensile, carbon alloy steel piston rods and one-piece steel piston, mechanically locked to the rod, ensures a long and trouble-free operating life.

A steel manifold and steel pipework have been engineered to offer exceptional levels of reliability, even under arduous conditions, and are designed to deliver optimum flow dynamics, improve system performance and reduce speed of response. The manifold can be connected directly to a wide range of industry-standard control valves, and can be supplied to fit NG6, NG10 and NG16 valve sizes, depending on the power and speed requirements of the application.

Parker is introducing the HMIX electro-hydraulic cylinders for designers and machine builders assembling a system from off-the-shelf, pre-assembled and tested components. Where a fully integrated electro-hydraulic axis control system is required, Parker offers purpose-built cylinders with dedicated control valve and digital controller, supplied complete and ready for installation.

HMIX electro-hydraulic cylinders are suitable for operating pressures up to 210bar and are available in a range of eight mounting styles, with bore sizes from 40-200mm and stroke lengths of up to 3000mm. Typical applications include machine tools, plastic injection moulding machines, welding machines and test equipment.

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