{HEAD ~ a spool} feeding back {TAIL ~ excess discharged oil} to a bypass passage of said pump in accordance with differential pressure between upstream and downstream sides of said variable throttle mechanism when said excess fluid exceeds a predetermined value; and 
feeding back
{ HEAD ~ a spool } feeding back { TAIL ~ excess discharged oil } to a bypass passage of said pump in accordance with differential pressure between upstream and downstream sides of said variable throttle mechanism when said excess fluid exceeds a predetermined value ; and
HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH