Bucher QX Internal Gear Pumps | Official Distributor, Stock

Official Bucher distributor
Warranty up to 12 months
ATEX certifications on request
QX, QXEH and QXEHX series usually in stock

3.2–495.4 cm³/revQX series displacements (QX24-003 to QX81-500)

400 barMax intermittent pressure, QX and QXM

360 barMax continuous pressure, QX range 4 (sizes 2–4)

6,050 rpmMax speed QXEHX (QXEHX32-010, mineral oil)

722 l/minQX81-500 flow at 1,450 rpm

up to 98%QX series volumetric efficiency

Prefer to talk to a technician? +39 0331 772410 · info@interfluid.net

Bucher QXEHX internal gear pump — **Bucher QXEHX**Internal gear pump for variable-speed drives, from 10 to 160 cm³/rev and up to 280 bar intermittent.

Interfluid, with its well-established experience in the field of internal gear pumps, is proud to offer Bucher's QX series, a prominent product in the mobile and industrial hydraulic markets.

This fifth-generation pump combines a simple design with exceptional compactness and robustness.

Thanks to its unique gear profile created by Bucher, the QX series stands out for its minimal pulsations and significantly reduced noise emissions, achieving values below 75 dB(A). This model is ideal for an open circuit and can handle a maximum working pressure of 400 bar.

It also offers a wide range of displacements, with capacities ranging up to 500 cm3/rev. Its versatility is highlighted by its compatibility with various hydraulic fluids and the ability to be used with both fixed and variable-speed drives. Its extended lifespan makes it a reliable solution for many applications. And, thanks to our well-stocked inventory, we ensure quick responses and timely deliveries to customer requests.

The QXEH series is available with single and double pump configurations. The use of precision-made internal components (e.g., the pinion shaft made in a single piece) allows for extremely low pulsation and flow values even at low speeds.

These pumps guarantee maximum reliability and high performance in highly dynamic variable speed applications and even in reversible operation.

The QXEHX series is, in fact, an evolution of the QXEH, developed specifically for use with variable speed drives up to 6050 rpm.

Hydrodynamic lubrication has been improved compared to the previous version, significantly increasing the pump's operational reliability.

This series is characterized by resistance to cavitation, even with critical fluids, and has a long lifecycle even with cyclic loads. Built with very durable materials, it is suitable for use in challenging environments and with various types of fluids.

The QXM series represents a sophisticated evolution of the QX pumps, versatile enough to operate as both a pump and a motor (2 and 4 quadrants). Their symmetrical structure makes them ideal for multidirectional operation, finding their place in a wide variety of hydraulic applications, both in industrial and mobile settings.

The QXM series easily handles pressures up to 400 bar in both open and closed circuits, maintaining noise emissions below 75 dB(A). Additionally, it is compatible with various hydraulic fluids and adapts perfectly to both fixed and variable speed drives.

On the other hand, the QXEM series is suitable for operation in medium-pressure circuits up to 250 bar.

Technical data by series

Six Bucher internal gear pump families, each designed for a different drive concept. Values for HLP mineral oil; actual displacements from the Bucher catalogue.

Series	Function	Displacement (cm³/rev)	Continuous pressure (bar)	Intermittent pressure (bar)	Max speed (rpm)
QX	Pump, fixed or variable speed	3.2–495.4	100–360 (depending on pressure range)	125–400	3,600
QXM	Pump/motor, 2 and 4 quadrants, open and closed circuit	5.1–495.4	100–320	125–400	4,000 pump / 6,000 motor
QXEH	Pump for variable speed, also in reversal	10–247.7	250	280	5,500
QXEHX	Pump for very high speeds, successor of the QXEH	10–159.7	210–250	250–280	6,050
QXEM	Multi-quadrant pump/motor, symmetrical design	5.1–247.7	210	250	3,250 pump / 6,000 motor
QYEH	Pump for variable speed, non-compensated, clockwise or counter-clockwise rotation	10–124.2	250	280	5,500

QX series, pressure range	Codes	Displacement (cm³/rev)	Continuous pressure (bar)	Intermittent pressure (bar)
Range 1	QX21 … QX81	10.3–495.4	100–160	125–210
Range 2	QX22 … QX82	5.1–247.7	210	250
Range 3	QX23 … QX83	5.1–247.7	320	400
Range 4	QX24 … QX84	3.2–247.7	320–360	400

Maximum speed refers to the smallest size of each series; it is lower on larger sizes. Intermittent operation: max 20 s per minute, not more than 10% of the cycle (QX, QXM, QXEM) or 40% (QXEH, QXEHX, QYEH). For the final selection, refer to the current Bucher catalogue.

Common features

Fluids: HLP mineral oils (DIN 51524-2) and HFC (VDMA 24317); QXM and QXEM also HFB and HFD
Operating viscosity 10–100 mm²/s, at start-up 10–300 mm²/s
Maximum contamination ISO 4406 20/18/15
Mineral oil temperature -20…+80 °C, ideal +30…+60 °C
2-bolt flange ISO 3019/1 (SAE) or ISO 3019/2 (metric), depending on size
NBR seals as standard, FPM (Viton) as an option
QX and QXM: ATEX II 3G version (T3/T4)
QX, QXEH, QXEHX and QYEH also available as double pumps; QX also as triple pumps

How to read the code

Example QX53-040R: QX series, size 5, pressure range 3, nominal displacement 40 cm³/rev, right-hand rotation
Sizes: 2, 3, 4, 5, 6, 8
Pressure range (QX): 1 = 100–160 bar, 2 = 210 bar, 3 = 320 bar, 4 = 320–360 bar continuous
Rotation: R = clockwise (standard), L = counter-clockwise, seen from the shaft side
Frequent options: 06 = external drain, 09 = FPM (Viton) seals
Double pump: QXEH42-025//32-016R06-ME (pump 1 // pump 2)

Bucher internal gear pump series compared

The six Bucher internal gear pump families share the same core strengths, very low noise, low flow pulsation and long service life, but each one is designed for a different drive concept. The table summarises the main ratings; full curves, noise values and dimensions are in the Bucher catalogues.

Series	Function	Circuit	Continuous pressure (bar)	Intermittent pressure (bar)	Displacement (cm³/rev)	Max speed (rpm)
QX	Pump, fixed or variable speed	Open	100–360 (depending on pressure range)	125–400	3.2–495.4	3,600
QXM	Pump/motor, four-quadrant	Open/closed	100–320	125–400	5.1–495.4	4,000 pump / 6,000 motor
QXEH	Pump, variable speed with reversal	Open	250	280	10–247.7	5,500
QXEHX	Pump, high dynamics and very high speed	Open	210–250	250–280	10–159.7	6,050
QXEM	Pump/motor, highly dynamic multi-quadrant	Open/closed	210	250	5.1–247.7	3,250 pump / 6,000 motor
QYEH	Pump, variable speed, reversible, robust design	Open	250	280	10–124.2	5,500

Which Bucher series should you choose?

QX: constant-speed electric motor, general industrial and mobile hydraulics (presses, machine tools, power units, forklifts). The most versatile series, up to 400 bar intermittent.
QXEH: servo-pump drives with variable speed and speed reversal (injection moulding, die casting, presses). Choose its successor QXEHX when you need higher speed, up to 6,050 rpm, and more power density.
QXM: energy recovery and four-quadrant operation, where the unit works as a pump while lifting and as a motor while lowering, up to 400 bar.
QXEM: highly dynamic cyclic loads in multi-quadrant operation, up to 250 bar.
QYEH: compact variable-speed drives in harsh conditions, with high cyclic loads or critical fluids, thanks to a non-compensated design with only two moving parts.

Not sure which code you need? Send us the nameplate data or the code of the pump you use today, also from other brands, and our technicians will find the right Bucher model – request a quote.

Technical data from Bucher Hydraulics documentation. Always refer to the current Bucher catalogue for the final selection.

Already a registered customer? Check stock of Bucher QX, QXEH and QXEHX pumps on Fluid-Hub.net, with an extra 2% discount.

Frequently asked questions

What is the difference between Bucher QX and QXEH?

The QX is the versatile pump for fixed or variable speed motors, up to 360 bar continuous and 400 bar intermittent. The QXEH is designed for variable-speed servo-pumps, also with speed reversal, up to 250 bar continuous and 5,500 rpm.

When should I choose the QXEHX instead of the QXEH?

When you need higher speeds: the QXEHX is the successor of the QXEH, with maximum speeds increased by about 20% (up to 6,050 rpm for the QXEHX32-010) and overlapping displacements from 10 to 160 cm³/rev.

QXM or QXEM for pump/motor operation?

Both work as pump and as motor in 2 and 4 quadrants. The QXM reaches 400 bar intermittent (320 continuous) up to 250 cm³/rev; up to 500 cm³/rev it is available in pressure range 1 (160 bar continuous, 210 intermittent); the QXEM, with a one-piece pinion shaft, is for circuits at 210 bar continuous and 250 intermittent up to 250 cm³/rev.

What data do I need to request a Bucher internal gear pump?

Send us the code of the pump you use today or its nameplate data: we check displacement, pressure, direction of rotation and connections before proposing the Bucher code.

How soon will I receive price and availability?

A technician will reply within 24 working hours.

Can't find the code you need?Send us the nameplate data or the code of the pump you use today, also from other brands: our technicians will find the right Bucher model. A technician will reply within 24 working hours.

Request price and availability

Bucher internal gear pumps

Series	Average stock	Discover online availability
from QX2 to QX8	✅ Usually available
from QXEH32 to QXEH82	✅ Usually available
from QXEHX42-020 to QXEHX52-080	✅ Usually available
from QXM2 to QXM8	🚚 Orderable from the supplier	⌛ Soon online
from QXEM2 to QXEM8	🚚 Orderable from the supplier	⌛ Soon online

Bucher QX series internal gear pump catalogueDownload Bucher QX series internal gear pump catalogue
Bucher QXEH series internal gear pump catalogueDownload Bucher QXEH series internal gear pump catalogue
Bucher QXEHX series internal gear pump catalogueDownload Bucher QXEHX series internal gear pump catalogue
Bucher QXM series internal gear pump catalogueDownload Bucher QXM series internal gear pump catalogue
Bucher QXEM series internal gear pump catalogueDownload Bucher QXEM series internal gear pump catalogue

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