Noise Reduction by Means of Non-Uniform Placement of Pistons in a Fluid Power Machine

In conventional machines, the pulsations are periodic and originate from the uniform placement of a given number of pistons. This paper discusses the possibilities to introduce nonuniform placement of the pistons. The pulsations’ periodicity is thus changed, which can have a major impact on the noise level and how the noise is experienced. A number of approaches are presented, evaluated and ranked and the usefulness of the modifications is assessed. This study employs a transfer function methodology to map simulated internal pump dynamics, such as piston forces and bending moments, to audible noise. Using these transfer functions, it is possible for instance to predict how changed valve plate timing affects simulated piston forces and bending moments and in turn how this will affect audible noise.