Hydraulic pump reservoir having deaeration diffuser

A hydraulic fluid reservoir for a hydraulic power system, comprising:

• a reservoir having an internal chamber for containing a supply of hydraulic fluid, an outlet for communicating fluid from said housing to an inlet of a hydraulic pump, and a return flow inlet for receiving a return flow of fluid into said chamber;
• and
• a flow diffuser having a diffuser inlet communicating with said return flow inlet for receiving at least a fraction of the return flow into said diffuser and having an inner fluid guide wall that diverges in a downstream direction and which is operative to slow the velocity of at least said fraction of return flow received into said diffuser through controlled expansion of the cross-sectional area of the at least said fraction of return flow as it advances along said diverging inner fluid guide wall, and a diffuser outlet communicating with said chamber for introducing the slowed velocity hydraulic fluid into said chamber where it can deaerate.