Description
Bucher QXEM Variable-Speed Internal Gear Pump and Motor Unit

The QXEM is intended for highly dynamic variable-speed operation as both a pump and a motor. Bucher describes the unit for multi-quadrant systems with fast reversal and cyclic loads. The series’ internal gear design and lubrication arrangements are specified for reliable operation within the published limits.
This INTEREQ listing covers the Bucher Hydraulics QXEM product family for identification, replacement enquiries and quotation support. Its product image is an original family illustration and does not depict a confirmed part number or selected configuration. Options and limits vary within a series; confirm the complete manufacturer code before ordering.
Technical specifications
| Brand | Bucher Hydraulics |
| Series / model codes | QXEM2, QXEM3, QXEM4, QXEM5, QXEM6 and QXEM8 |
| Component | Internal gear pump/motor unit for dynamic multi-quadrant service |
| Design | Symmetrical internal gear unit for variable-speed pump and motor operation with rapid reversing. |
| Displacement | 5–250 cm³/rev across listed models |
| Pressure | Up to 210 bar continuous and 250 bar intermittent |
| Maximum speed | Pump: up to 3,250 rpm; motor: up to 6,000 rpm, model dependent |
| Hydraulic circuit | Open- or closed-circuit multi-quadrant applications |
| Availability | Quotation on request; exact configuration and availability confirmed for the selected unit. |
Applications
Injection-moulding machines, hydraulic presses, waste compactors, pressure die-casting equipment and other industrial systems with frequent load changes. Final suitability depends on the machine, hydraulic circuit, duty cycle and installed component configuration. Check the equipment documentation and the manufacturer’s current data before specifying a replacement.
Key features and compatibility
The manufacturer lists low noise, compatibility with almost all hydraulic fluids and fixed- or variable-speed drive options. Each frame has a distinct displacement, pressure and speed envelope; the series maximums must not be combined arbitrarily. Confirm circuit design, load profile, rotation, fluid and full order code before selection. Interfaces are model-specific. Do not assume that units sharing a series name have matching shafts, flanges, ports, rotation, controls or seals. Published family ranges are identification guides and must not be treated as ratings for every size or combination.
Model identification and replacement selection
Do not select a replacement by brand and series alone. Compare the full nameplate code and confirm displacement, rotation, shaft, mounting flange, port arrangement, controls, case-drain requirements and hydraulic circuit against the installed unit and machine documentation. Send INTEREQ a clear nameplate photo and machine make/model for identification.
For a quotation, provide the full type code, machine model, operating conditions and any available drawing or nameplate image. Condition, availability and technical fit are confirmed for the specific unit offered.
System sizing and replacement check
For system sizing, compare pump displacement and shaft speed with the required flow, then check continuous and intermittent pressure against the machine duty cycle. Confirm inlet conditions, fluid viscosity and cleanliness, operating temperature, case pressure where applicable, drive power and external shaft loads. These conditions affect performance and service life; a series maximum is not an operating target for every unit.
When the installed type code is incomplete, include clear photos of the nameplate, mounting face, shaft and port layout. Provide the machine make/model, current circuit details and operating conditions so the replacement can be checked against the correct manufacturer data sheet.
Related Bucher Hydraulics product families
Hydraulic service parts and supply
For maintenance or repair of the Bucher QXEM Variable-Speed Internal Gear Pump and Motor Unit, INTEREQ can source and supply compatible hydraulic service parts, including pumps, motors, control valves and related components. We check the complete type code, machine or system application, compatibility and availability before quotation.
Browse all Hydraulic Pumps & Motors or view Bucher hydraulic products.
Manufacturer reference: Bucher Hydraulics product information for the QXEM family.
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