Hydraulic pump

A hydraulic pump comprising:

• a valve plate including a suction port and a delivery port;
• a valve cover to which the valve plate is mounted, the valve cover including a suction passage that communicates with the suction port and a delivery passage that communicates with the delivery port;
• and
• a cylinder block that slides on the valve plate, the cylinder block including cylinder bores that receive therein respective pistons, wherein
• the valve cover includes:
• a first chamber that communicates with the delivery passage through a communication passage and functions as a Helmholtz resonator;
• and
• a second chamber that communicates with the delivery passage, or with the first chamber, through an introduction passage, and
• in the valve cover and the valve plate, a supply passage extends from the second chamber to a bottom dead center-side sealing surface of the valve plate, the bottom dead center-side sealing surface being a surface located between the suction port and the delivery port.