Brueninghaus

Brüninghaus was a German manufacturer of hydraulic components that specialized in axial piston pumps and axial piston motors. The company emerged from the Brüninghaus steelworks and was integrated into the Rexroth Group in the 1970s. Today, the brand has been fully absorbed into Bosch Rexroth AG. The pump and motor series developed under the Brüninghaus name continue to shape the hydraulics industry to this day.

History and Development of Brüninghaus

The history of Brüninghaus is closely linked to the development of the German hydraulics industry. The company began as a division of the Brüninghaus Steelworks, a traditional steel processing company based in the Westphalia region during the first half of the 20th century. The hydraulics division evolved out of the need to manufacture hydraulic drive components for industrial applications.

From Steel Mill to Hydraulics Specialist

In 1957, the plant in Horb am Neckar was founded to establish series production of axial piston machines. It started with 80 employees who produced the first industrial batch of axial piston pumps. This step marked the transition from custom-made products to mass-produced hydraulic components, which would later set industry standards. In 1969, the hydraulics division was spun off from the steelworks as an independent company, Brueninghaus Hydraulik GmbH.

Acquisition by Mannesmann Rexroth

Between 1975 and 1976, Mannesmann AG acquired the company and integrated it into the Rexroth Group. Rexroth thereby purposefully expanded its expertise in the field of axial piston machines. Brüninghaus contributed an established product line of swashplate axial piston pumps covering the medium-pressure range, while the Rexroth brand Hydromatik specialized in swashplate axial piston pumps for higher pressure ranges. This complementary focus of the two brands proved to be strategically advantageous.

Merger to Form Brueninghaus Hydromatik GmbH

In 1994, the two Rexroth subsidiaries, Brüninghaus and Hydromatik, merged to form Brüninghaus Hydromatik GmbH. The new company operated from two locations: Horb am Neckar, the original Brüninghaus production site, and Elchingen, the traditional Hydromatik location. This merger brought together all expertise in axial piston pumps and axial piston motors under one roof and strengthened the company’s market position in the face of global competition.

Transition to Bosch Rexroth AG

In 2001, Robert Bosch GmbH acquired the Rexroth Group and integrated the hydraulics business into the Bosch Group. Brueninghaus Hydromatik GmbH initially continued to operate as a subsidiary until it was fully merged into Bosch Rexroth AG in 2010. Since then, Bosch Rexroth has been the sole brand name. However, the product series developed under the Brüninghaus name continue to be produced and further developed.

Brüninghaus Product Portfolio

Brüninghaus’s core area of expertise lay in the development and manufacture of axial piston pumps and axial piston motors. These machines are among the most important drive components in hydrostatic systems and convert hydraulic energy into mechanical rotational energy and vice versa.

Axial piston pumps with swivel angle adjustment

Brüninghaus played a key role in the further development of axial piston pumps with adjustable swivel angle. In this design, the angle of inclination of the swivel disc can be adjusted during operation, allowing the displacement volume—and thus the flow rate—to be continuously regulated. This adjustment principle enables demand-based flow control without having to change the drive speed. Pumps of this design are used in numerous industrial and mobile applications where hydrostatic drives must be precisely controlled.

Constant-Volume Pumps and Fixed-Displacement Motors

In addition to variable-displacement pumps, the product portfolio also included constant-displacement pumps with a fixed displacement volume. This series was primarily used in applications where a constant flow rate is sufficient and adjustability is not required. When operated as motors, axial piston machines convert hydraulic pressure into torque, with constant-displacement motors offering a simple and robust solution for many drive tasks.

Well-Known Brüninghaus Series

The product series marketed under the name Brüninghaus—and later Brueninghaus Hydromatik—have achieved a level of recognition in the hydraulics industry that extends far beyond the company’s history. The series designations are still used today in the spare parts business and in technical documentation.

The A2F Series

The A2F series comprises axial piston machines with an oblique-axis design and a fixed displacement volume. It is used both as a pump and as a motor. The swashplate design is characterized by a fixed angle between the drive shaft and the cylinder axis, typically 25 degrees. A2F machines are suitable for hydrostatic drives in open and closed circuits and are found in industrial plants as well as in mobile machinery. The series includes several sizes that differ in displacement and cover various power ratings.

The A2V Series

The A2V series consists of variable-displacement pumps. Displacement is adjusted by changing the swivel angle of the swivel disc. For the A2V series, nominal pressures up to 350 bar and peak pressures up to 400 bar are documented. For pulsating pressures above 315 bar, the manufacturer recommends using spur gear shaft versions instead of spline shafts to reduce shaft load. A2V pumps are used in applications with variable flow rate requirements, such as presses, injection molding machines, and other industrial systems with varying load profiles.

The A2VK Series

The A2VK series is a more compact line of variable-displacement pumps designed specifically for medium-pressure ranges. The nominal pressure range is up to 250 bar, with a maximum pressure of 315 bar at the ports. The series includes several sizes with displacement volumes ranging from approximately 12 to 107 cm³ per revolution. The A2VK pumps are intended for applications in the medium-capacity range and are frequently used in small- to medium-sized industrial hydraulic systems. These pumps also play a role in the aftermarket, as many older systems are equipped with A2VK pumps and continue to be maintained.

Technical Features and Design Principles

The axial piston pumps developed by Brüninghaus are based on proven design principles that remain relevant in hydraulic engineering to this day. Two designs dominate the product portfolio: oblique-axis and swivel-disc pumps.

Oblique-Axis Design

In the oblique-axis design, the piston axes are arranged at a fixed angle to the drive shaft. The cylinders operate eccentrically relative to the drive shaft and transmit the piston force to the drive disc via connecting rods. This design allows for high pressure loads and is characterized by a compact configuration. Oblique-axis machines in the A2F series achieve efficiencies that rank among the highest in hydraulic machinery.

Swivel Disc Design

The swivel-disc design uses an adjustable angle of inclination of the swivel disc to vary the displacement volume. The pistons move parallel to the drive shaft and are supported by the swivel disc. This design allows for stepless adjustment of the flow rate and forms the basis of the A2V and A2VK variable-displacement pumps. Designers choose this design when variable flow rates are required in conjunction with a compact design.