Abstract: A vane pump includes a casing and a rotary unit rotatably held within the casing. The rotary unit includes a base portion with radially outwardly opened slits extending radially with respect to a rotational axis of the rotary unit and vanes slidably fitted in the respective slits. An annular chamber is formed around the base portion within the casing and divided into a plurality of pump chambers by the vanes. Each of the pump chambers has a volume cyclically expanded and contracted during rotation of the rotary unit to discharge the fluid drawn into each of the pump chambers. The casing includes an inlet port through which to draw the fluid into the annular chamber. The inlet port is arranged to face a portion of the annular chamber extending between a middle position and a terminating position of an expanding section in which each of the pump chambers expands.

Abstract: A vane pump includes a casing and a rotary unit rotatably held within the casing. The rotary unit includes a base portion with radially outwardly opened slits extending radially with respect to a rotational axis of the rotary unit and vanes slidably fitted in the respective slits. An annular chamber is formed around the base portion within the casing and divided into a plurality of pump chambers by the vanes. Each of the pump chambers has a volume cyclically expanded and contracted during rotation of the rotary unit to discharge the fluid drawn into each of the pump chambers. The casing includes an inlet port through which to draw the fluid into the annular chamber. The inlet port is arranged to face a portion of the annular chamber extending between a middle position and a terminating position of an expanding section in which each of the pump chambers expands.

Abstract: A vane pump includes slits formed in a base portion of a rotary unit rotating in a casing and extend radially from a rotation axis of a rotary unit to be opened outwardly in a radial direction, a vane received in each of the slits to be protruded from or retreated into the slit, an annular chamber formed around the base portion in the casing and pump rooms formed by defining the annular chamber by using the vanes. The vane pump is operated to discharge fluid sucked into an associated pump room by rotating the rotary unit and thereby periodically increasing or reducing volume of the pump rooms. The vane pump further includes a fluid force generating portion provided on at least one of the rotary unit and the casing to generate fluid force to the upper side in an axial direction of the rotation axis by rotation of the rotary unit.