Vane pump with variable discharge volume

Abstract

The present invention relates to a vane pump with variable discharge volume, and comprising a pump housing; a cam ring having an elliptical cross-section for its inner circumference and outer circumference to form a compression chamber wherein a compression medium is compressed, and is accommodated in said pump housing so that it may rote; a rotor hat is accommodated such that a plurality of vanes may appear frequently on the outer circumference to undergo rotations in the compression chamber of said cam ring and compress said compression medium; and a cam ring rotation controller that contacts the outer circumference of said cam ring, and rotates said cam ring if the discharge pressure of said compression medium is equal to or more than its pressure setting and stops the rotation of said cam ring if the discharge pressure of said compression medium is less than its pressure setting to control rotations of said cam ring. Accordingly, the rotation and stoppage of rotation of the cam ring is accomplished based on changes in the discharge pressure, to enable variation in discharge volumes, and enhancement of discharge efficiency.

1 . A vane pump with a variable discharge volume, comprising:
 a pump housing:   a cam ring of which inner and outer surfaces each have an elliptical cross section and which has a compression chamber for compressing a compressed medium and is rotatably accommodated in the pump housing:   a rotor which rotates in the compression chamber of the cam ring and compresses the compressed medium, with a plurality of vanes being formed in a radial shape on its outer surface and each being retractable; and   a cam ring rotation controller which comes into contact with an outer surface of the cam ring and rotates the cam ring when a discharge pressure of the compressed medium is higher than a set level and stops the rotation of the cam ring when a discharge pressure of the compressed medium is lower than a set level, thus controlling the rotation of the cam ring.   
     
     
         2 . A vane pump with a variable discharge volume according to  claim 1 , wherein said cam ring rotation controller comprises:
 a piston which comes into slidable contact with an outer surface of the cam ring and reciprocates depending on the rotation of the cam ring; and   a spring which provides an elastic force to the piston to stop the rotation of the cam ring when a discharge pressure of the compressed medium is lower than a set level.   
     
     
         3 . A vane pump with a variable discharge volume according to  claim 2 , wherein when a discharge pressure of the compressed medium is higher than a set level, the cam ring rotates, and the piston moves toward the spring, thus compressing the spring. 
     
     
         4 . A vane pump with a variable discharge volume according to  claim 2 , wherein said cylinder control controller further comprises a spring adjusting bolt for adjusting the displacement of the spring. 
     
     
         5 . A vane pump with a variable discharge volume according to  claim 2 , further comprising:
 a rod which is disposed between the piston and the spring and ascends and descends by means of a discharge pressure of the compressed medium, thus transferring an elastic force of the spring to the piston, and inclined parts having opposed inclination directions are formed at the end portions of the piston and the rod in which the piston and the rod come into contact with each other.   
     
     
         6 . A vane pump with a variable discharge volume according to  claim 1 , further comprising a suction side plate which forms a suction passage for guiding a suction of a compressed medium into the compression chamber and is formed at one side of the cam ring; and a discharge side plate which forms a discharge passage for guiding the discharge of the compressed medium compressed in the compression chamber and is installed opposite to the suction side plate about the cam ring.