Applications with external shaft loads
External loads are found in applications where the pump is driven with a side/thrust load (belt drive or
gear drive) as well as in installations with misalignment and improper concentricity between the pump
and drive coupling. All external loads act to reduce bearing life.
In applications where you cannot avoid external radial shaft loads, orient the load to 0° or 180° position.
Use tapered output shafts or clamp-type couplings where radial shaft loads are present.
In addition, external thrust loads can reduce bearing life in systems with low delta pressure or in
combination with external radial loads/bending moments.
Re = Me / L
Me = Shaft moment
L = Flange distance
Re = External force
Radial load position
B
A
P108 549E
0°Re
90°
Re
270°
Re
180°Re
L
Re
Maximum allowable external shaft load
Parameter
042
055
075
100
130
180
250
External moment (Me)
N•m [lbf•in]
126
[1114]
101
[893]
118
[1043]
126
[1114]
140
[1238]
*
*
* no tapered shaft available
If continuous applied external radial loads are 25% of the maximum allowable or more or thrust loads/
bending moments known to occur, contact your Danfoss representative for an evolution of bearing life.
Avoid external thrust loads in either direction.
Understanding and Minimizing System Noise
Noise is transmitted in fluid power systems in two ways: as fluid borne noise, and structure borne noise.
Fluid-borne noise (pressure ripple or pulsation) is created as pumping elements discharge oil into the
pump outlet. It is affected by the compressibility of the oil, and the pump's ability to transition pumping
elements from high to low pressure. Pulsations travel through the hydraulic lines at the speed of sound
(about 1400 m/s [4600 ft/sec] in oil) until there is a change (such as an elbow) in the line. Thus, amplitude
varies with overall line length and position.
Structure born noise is transmitted wherever the pump casing connects to the rest of the system. The
way system components respond to excitation depends on their size, form, material, and mounting.
System lines and pump mounting can amplify pump noise.
Follow these suggestions to help minimize noise in your application:
Technical Information
Series 90 Axial Piston Pumps
System Design Parameters
520L0603 • Rev 0804 • March 2016
17
