Vane pump

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.

1 . A vane pump comprising:
 a plurality of slits which are 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;   a plurality of pump rooms formed by defining the annular chamber by using the plurality of vanes, the vane pump being 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; and   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.   
   
   
       2 . The vane pump of  claim 1 , wherein a guide wall is provided on the rotary unit and placed on the lower side in the axial direction of the rotation axis to be in sliding contact with an associated vane. 
   
   
       3 . The vane pump of  claim 1 , further comprising:
 a thrust support unit for slidably supporting the rotary unit against the casing, the rotary unit being rotated by the fluid force applied to the upper side in the axial direction,   wherein a diameter of a sliding portion of the thrust support unit is smaller than a diameter of the base portion.   
   
   
       4 . The vane pump of  claim 1 , wherein the fluid force generating portion is provided on the rotary unit, and includes a slanting surface which is inclined with respect to a rotating direction of the rotary unit. 
   
   
       5 . The vane pump of  claim 1 , wherein the fluid force generating portion is provided on the rotary unit, and includes a wing brought into contact with a counter flow of the fluid resulting from rotation of the rotary unit. 
   
   
       6 . The vane pump of  claim 1 , wherein the fluid force generating portion is provided on the rotary unit, and includes a spiral projection or groove formed around the rotation axis. 
   
   
       7 . The vane pump of  claim 1 , wherein the fluid force generating portion is provided on the casing, and includes a protrusion which is opposite to the rotary unit in such a way as to protrude towards the rotary unit. 
   
   
       8 . The vane pump of  claim 1 , wherein the rotary unit includes a cylindrical skirt portion which is concentric with the rotation axis and protrudes towards the lower side in the axial direction, and a cylindrical gap is formed between the skirt portion and the casing. 
   
   
       9 . The vane pump of  claim 8 , further comprising:
 a magnetized portion provided on the skirt portion;   a stator core including a coil provided inside the skirt portion; and   a motor having the magnetized portion and the stator core which are arranged in a radial direction of the rotation axis of the rotary unit to be spaced apart from each other.