Bucher’s New Hydraulic Pumps, Motors

Bucher Hydraulics has launched its new AX piston pumps and motors into North America. The new units, which will be available in multiple sizes with displacements from 18 to 76 cc/rev, are designed to overcome what the company sees as the limitations of conventional hydraulic pumps and motors.

The AXFP fixed displacement piston pump (shown), which was first unveiled at Bauma 2019, is based on a new concept in which the internal forces are balanced by having two rotating barrel plates with 12 piston each facing each other. This, Bucher said, enables high power density while at the same time limits the axial forces to the point where only a light bearing is required to absorb them.

Bucher said the characteristics of the AX pump – a high volumetric and mechanical efficiency, low noise, low pressure ripple, minimum speeds as low as 2 rpm and bi-directional capability – make it well suited toward hybrid or electric machines

In winch drive applications, standard AX pumps and motors can reach a working pressure of 6500 psi (450 bar), while at the same time offering a low-speed operating range of just a few rpm. That gives the AX motor a start efficiency of 99% versus the 60% to 65% efficiency of a conventional axial-piston unit, Bucher said.

In wheel motors, the high power density, high working pressure and low speed make the AXM motor an alternative to gear motors. The minimum speed of 2 rpm at high pressure offers new options for mobile machines, such as crawler excavators where the volumetric efficiency of approximately 96% could increase ground speed, the company said.