Control Valve Apparatus

Abstract

In a hydraulic system equipped with a main flow passage for feeding oil to each of lubricated engine parts and a branch passage branched from the main flow passage, a control valve apparatus is provided for adjusting a flow rate of the oil flowing through a portion of the main flow passage downstream of the branched point. The control valve apparatus is configured to control openings of a large flow control section and a small flow control section, depending on a position of a valve element, and further configured to close the opening of the small flow control section, at least in a specified state where the opening of the large flow control section is fully opened with a maximum opening area.

1 . In a hydraulic system equipped with a main flow passage for feeding oil, discharged from an oil pump driven by an internal combustion engine, to each of lubricated engine parts, a branch passage branched from the main flow passage at a branched point, and a hydraulic actuator operated by a hydraulic pressure in the branch passage, the combination of:
 a control valve apparatus for adjusting a flow rate of the oil flowing through a portion of the main flow passage downstream of the branched point,   the control valve apparatus configured to control an opening of a large flow control section and an opening of a small flow control section whose opening area is less than that of the large flow control section, depending on a position of a valve element disposed in the portion of the main flow passage downstream of the branched point, and   the control valve apparatus further configured to close the opening of the small flow control section, at least in a specified state where the opening of the large flow control section is fully opened with a maximum opening area.   
     
     
         2 . In a hydraulic system equipped with a main flow passage for feeding oil, discharged from an oil pump driven by an internal combustion engine, to each of lubricated engine parts, a branch passage branched from the main flow passage at a branched point, and a hydraulic actuator operated by a hydraulic pressure in the branch passage, the combination of:
 a control valve apparatus for adjusting a flow rate of the oil flowing through a portion of the main flow passage downstream of the branched point,   the control valve apparatus comprising a sliding-contact bore into which an inlet of the main flow passage opens and from which an outlet of the main flow passage opens, and a spool installed to axially move in the sliding-contact bore only as needed, the sliding-contact bore and the spool both disposed in the portion of the main flow passage downstream of the branched point, and the spool has a first communication passage intercommunicating the inlet and the outlet and a second communication passage intercommunicating the inlet and the outlet and having an opening area less than an opening area of the first communication passage,   the control valve apparatus configured to bring the first communication passage to a communicated state and simultaneously to bring the second communication passage to a non-communicated state, in a first state where the spool has moved with a maximum displacement in one axial direction of the spool, and   the control valve apparatus further configured to bring the second communication passage to a communicated state and simultaneously to bring the first communication passage to a non-communicated state, in a second state where the spool has moved with a maximum displacement in the opposite axial direction of the spool.   
     
     
         3 . The control valve apparatus as claimed in  claim 2 , wherein:
 the inlet of the main flow passage is configured to open from a sliding-contact surface of the sliding-contact bore in sliding-contact with the spool, whereas the outlet of the main flow passage is configured to open from a first axial end of two opposite axial ends of the sliding-contact bore,   the first and second communication passages are formed separately from each other in a sliding-contact surface of the spool in sliding-contact with the sliding-contact bore, and   the first and second communication passages are configured to be merged with each other by an axial passage formed in the spool along a centerline of the spool, and then communicated with the outlet of the main flow passage.   
     
     
         4 . The control valve apparatus as claimed in  claim 3 , wherein:
 the displacement of the spool is electronically controlled.   
     
     
         5 . The control valve apparatus as claimed in  claim 4 , wherein:
 the axial passage is configured to open from only a first axial and of two opposite axial ends of the spool,   a pressure-receiving surface area of the second axial end of the spool is dimensioned to be greater than a pressure-receiving surface area of the first axial end formed with the axial passage, and   a hydraulic pressure in the main flow passage is selectively supplied or exhausted to or from the second axial end of the spool by an electromagnetic valve.   
     
     
         6 . The control valve apparatus as claimed in  claim 5 , wherein:
 the second axial end of the spool has a cylindrical bore formed therein.   
     
     
         7 . The control valve apparatus as claimed in  claim 5 , wherein:
 the oil in the inlet of the main flow passage is introduced into the second axial end of the spool.   
     
     
         8 . The control valve apparatus as claimed in  claim 5 , wherein:
 the sliding-contact bore, the spool, and the electromagnetic valve are installed in the internal combustion engine in the form of a valve unit with the spool, the electromagnetic valve, and a housing, which defines therein the sliding-contact bore.   
     
     
         9 . The control valve apparatus as claimed in  claim 3 , wherein:
 the first axial end of the sliding-contact bore, from which the outlet of the main flow passage opens, is formed with a through hole whose inside diameter is dimensioned to be less than an inside diameter of the sliding-contact bore in sliding-contact with the spool to form a small-diameter bottom, and the small-diameter bottom constructs a stopper that restricts the maximum displacement of the spool in the opposite axial direction.   
     
     
         10 . In a hydraulic system equipped with a main flow passage for feeding oil, discharged from an oil pump driven by an internal combustion engine, to each of lubricated engine parts, a branch passage branched from the main flow passage at a branched point, and a hydraulic actuator operated by a hydraulic pressure in the branch passage, the combination of:
 a control valve apparatus for adjusting a flow rate of the oil flowing through a portion of the main flow passage downstream of the branched point,   the control valve apparatus comprising a sliding-contact bore into which an inlet of the main flow passage opens and from which an outlet of the main flow passage opens, and a spool installed to axially move in the sliding-contact bore selectively between two opposite axial positions only as needed, the sliding-contact bore and the spool both disposed in the portion of the main flow passage downstream of the branched point, and the spool has a first communication passage intercommunicating the inlet and the outlet and a second communication passage intercommunicating the inlet and the outlet and having an opening area less than an opening area of the first communication passage,   the control valve apparatus configured to bring the first communication passage to a communicated state and simultaneously to bring the second communication passage to a non-communicated state, in a first state where the spool has moved to one of the two opposite axial positions, and   the control valve apparatus further configured to bring the second communication passage to a communicated state and simultaneously to bring the first communication passage to a non-communicated state, in a second state where the spool has moved to the opposite axial position.