Vane pump housing

A vane pump comprising:

• a casing having therein a bore with a substantially circular profile and fluid inlet and outlet ports respectively communicating with said bore;
• an annular resilient sleeve disposed in said bore so that the centers of said bore and said annular resilient sleeve are offset eccentrically, and having formed therein a pair of apertures respectively communicating with said inlet and outlet ports, said annular resilient sleeve having a wall thickness substantially uniform throughout the whole thereof;
• a rotor rotatably disposed in said annular resilient sleeve and having a plurality of axial slots formed therein;
• a plurality of vanes slidable in respective slots, said vanes protruding radially from said rotor so as to sealingly contact the inner wall of said annular resilient sleeve, said rotor being rotatable about a center which is offset from the center of said bore by a predetermined amount;
• deforming means disposed in said casing to exert a deforming force inwardly on said resilient sleeve to increase the sealing contact between said sleeve and said vanes;
• said deforming means being arranged to deform said resilient sleeve a predetermined amount in a plane containing the two centers of said rotor and said bore;
• and
• said annular resilient sleeve being guided along the generally half peripheral cylindrical wall thereof by said circular profile of said casing.