Energy recovery with direct cylinder actuation
Saving costs and reducing energy consumption are significant factors in all areas of industry. There is a demand for economical, highly effective components and systems which operators can use to increase the performance levels of their plants and thus improve their competitiveness. Our modern hydraulic concepts with QX internal gear drive units provide solutions that set new standards with regard to cost effectiveness, particularly in industrial applications such as injection-molding or die-cast machinery, metal forming and recycling presses.
The enhanced QX series is what economists justifiably describe as genuine innovation. With decades of experience under our belt we keep a close eye on market trends, identify forward-looking technologies and implement them in new products. The QX series currently represents the fifth generation of internal gear drive units tried and tested all over the world and is a perfect example of this philosophy. The principle behind the QX untangles the complexity associated with axial and radial piston solutions used in many industrial applications in the past. Internal gear drive units with pump and motor functions utilized in 1, 2 and 4 quadrant applications meet even the most stringent drive demands in a cost-effective manner.
The QX internal gear drive unit becomes the genuine highlight of any hydraulic concept when combined with variable speed drives: It generates a variable flow rate so that the hydraulic oil supply reflects the actual requirement involved and directly drives actuators without the need for circuitous and energetically time-consuming detours through valves. This results in less pipe-work, lower hydraulic oil quantities, smaller tanks and consequently less cooling expenditure, all due to the fact that the heat loss level is very low. Users will also save energy and thus reduce their overall costs by bringing down cycle-times and providing energy feedback. The ability to adjust pump actuators in milliseconds is due to the dynamics of the QX series and is very close to the levels achieved by servo technology. This contributes towards higher productivity.
Excellent controllability and the resulting direct conversion of driving speed into hydraulic performance ensure that users of QX internal gear drive units conserve energy. Plant productivity is simultaneously increased because high velocity values shorten cycle times thanks to the low number of rotating components. This is where the QX series offers the user significantly more advantages when compared to other drive units, including sealing gap compensated internal gear pumps.
When permanently developing and enhancing these internal gear drive units, our primary target is efficiency: Q stands for both quadrant and quiet because this drive unit provides 1, 2 and 4 quadrant operation and is making a name for itself on the market as being a low noise product thanks to its low pulsation level. The X in the type nomenclature could well reflect the colloquial German expression for innumerable and is representative of the multitude of industrial applications in which the many features of these drive units are positive factors.
Threshold investigations into accelerations with a QX.62-10 pump Acceleration from 0 to 2750 min-1 in 70 ms
The QX series’ success is based on its detailed engineering. QX internal gear drive units have only a few moving parts which results in their significantly higher velocity values and ensuing shorter cycle times when compared to other drive types. "Less is more" additionally makes internal gear drives low in vibration, light compact, durable and safe in operation.
Furthermore, the high performance and reliability of Bucher Hydraulics’ internal gear drive units are based on finesse such as sealing surfaces and bearings. Enlarged sealing surfaces have a positive effect on efficiency and control behavior. The hydrodynamic design of the rotating components bearings also allows the QX internal gear drives to be safely used in operations at low speeds and high pressures.
Greater strength thanks to the improved stability of the rotating components low noise emission, even at high speeds, achieved by special non-evolvent gearing are examples of technical progress specifically aimed at current and future demands. This means that the internal gear drive unit’s low noise pressure level is well below machine manufacturers’ specifications with respect to quiet running. Internal gear drive units with their long pressure sustainment are also convincing in many industrial applications because the lubricat-ing film is kept stable during this phase as well. With its directly piloted consistent running and differential cylinders the drive unit works as a pump when lifting and/or accelerating and, when loads are lowered or retarded, as a motor to recover energy.
With their QX internal gear drive units Bucher Hydraulics provide their customers with a competitive edge and meet increasing de-mands for cost savings, noise reduction and ecological awareness.
Frequency controlled actuation with a QX drive unit Basic diagram of an open loop system