Check Valve for a Vacuum Pump

Abstract

A check valve 50 for a vacuum pump 1 is disclosed in which opening of the check valve 50 is controlled by centrifugal force by arranging a valve member 40 to slide along a slide axis Y-Y inclined with respect to an axis of rotation of a housing 27 in which the valve member 40 is slideably supported. The housing 27 rotates with a rotor 10 of the vacuum pump 1 and, in a one embodiment, the slide axis Y-Y is arranged at a right angle with respect to the axis of rotation X-X so as to maximize the effect of centrifugal force on the valve member 40 as the housing 27 is rotated.

1 . A vacuum pump connected to an oil supply, comprising:
 a pump housing;   a rotary pumping element disposed within said housing rotating about a pump axis; and   a valve mounted in said housing such that it rotates with the rotary pump element, wherein
 said valve is displaced from the centerline of said pump axis; 
 said valve has a valve member which moves linearly from an open position to a closed position; 
 said linear axis of said valve member forms a nonnegligible angle with said pump axis; 
 said valve has a spring, said spring biasing said valve member toward said pump axis; and 
 said valve member has an end face in fluid communication with the oil supply. 
   
     
     
         2 . The pump of  claim 1  wherein said nonnegligible angle is approximately 90°. 
     
     
         3 . The pump of  claim 1  wherein said valve is open when said valve member is displaced toward said valve axis and is closed when said valve member is displaced away from said valve axis. 
     
     
         4 . The pump of  claim 1  wherein said valve member has an end face, said valve member being acted upon by oil pressure from the oil supply on said end face, spring force, and centrifugal force, when said valve is rotating. 
     
     
         5 . The pump of  claim 4  wherein said valve member is displaced toward said valve axis when said spring force exceeds centrifugal force and the force of the oil pressure on said end face. 
     
     
         6 . The pump of  claim 1  wherein said spring reacts between an end cap fastened to said valve and said valve member. 
     
     
         7 . The pump of  claim 1  wherein said valve member has an end face and said valve has a tubular body portion extending away from said end face and the spring is located within the tubular body portion of said valve. 
     
     
         8 . The pump of  claim 1  wherein said end cap has a vent passage so that the interior of said tubular body portion is maintained at atmospheric pressure. 
     
     
         9 . The pump of claim wherein said valve has a valve chamber connected to the oil supply by an oil supply passage and when said valve member is in a closed position, said valve chamber remains in fluid communication with the oil supply passage. 
     
     
         10 . The pump of  claim 6 , further comprising: a second end cap fastened to said valve housing to provide an end stop for said valve member thereby determining the closed position of the valve member. 
     
     
         11 . The pump of  claim 1  wherein the rotary pumping element comprises a rotor and at least one sliding vane. 
     
     
         12 . The pump of  claim 1  wherein said pump supplies vacuum to engine accessories, and said pump is driven by one of a chain drive from an engine, a belt drive from the engine of the motor vehicle and an electric motor. 
     
     
         13 . A vacuum pump connected to an oil supply, comprising:
 a pump housing;   a rotary pumping element disposed within said housing rotating about a pump axis; and   a valve disposed within said housing and rotatable with said rotary pumping element wherein an axis along which a valve member within the valve slides forms substantially a right angle with the axis of rotation of said rotary pump;   said valve is displaced from the centerline of said pump axis; and   said valve member has an end face in fluid communication with the oil supply and said valve has a tubular body portion extending away from said end face and a spring is located within the tubular body portion.   
     
     
         14 . The pump of  claim 13  wherein said spring biases said valve member toward said pump axis. 
     
     
         15 . The pump of  claim 13  wherein said valve member has an end face and said valve member is moved against the action of said spring by a combination of centrifugal force and the oil supply pressure acting upon said end face of said valve member. 
     
     
         16 . The pump of  claim 13  wherein said centrifugal force is zero when said pump is not rotating such that said valve member is biased toward said pump axis by said spring to maintain said valve in a closed position. 
     
     
         17 . The pump of  claim 16  wherein said valve has a valve chamber connected to the oil supply by an oil supply passage and when said valve member is in a closed position, said valve chamber remains in fluid communication with the oil supply passage.