Valve timing controller

Abstract

A control valve is provided with a spool and a supply port through which an operating oil is supplied. The spool is provided with an advance check valve and a retard check valve. The advance check valve restricts an operating oil flow flowing from the advance chamber to the supply port and permits an operating oil flow flowing from the supply port to the advance chamber when the advance chamber communicates with the supply port. The retard check valve restricts the operating oil flow flowing from the retard chamber to the supply port and permits the operating oil flow flowing from the supply port to the retard chamber when the retard chamber communicates with the supply port. When a rotational phase of the camshaft is held at a target phase region, the advance chamber and the retard chamber communicate with the supply port respectively.

1 . A valve timing controller which adjusts a valve timing of a valve opened/closed by a torque transmitted from a crankshaft to a camshaft of an internal combustion engine, the valve timing controller comprising:
 a first rotating member rotating along with the crankshaft;   a second rotating member rotating along with the camshaft, and defining an advance chamber and a retard chamber in cooperation with the first rotating member in a rotating direction thereof, the second rotating member driving the camshaft in an advance direction or a retard direction relative to the crankshaft by receiving an operating fluid into the advance chamber or the retard chamber; and   a control valve provided with a spool and a supply port through which the operating fluid is supplied from a fluid supply source, the spool slidably moving so as to control a communicating condition of the advance chamber and the retard chamber to the supply port, wherein   the spool includes:
 an advance check valve which restricts an operating fluid flow flowing from the advance chamber to the supply port and permits the operating fluid flow flowing from the supply port to the advance chamber when the advance chamber communicates with the supply port; and 
 a retard check valve which restricts an operating fluid flow flowing from the retard chamber to the supply port and permits the operating fluid flow flowing from the supply port to the retard chamber when the retard chamber communicates with the supply port, and 
   the control valve moves the spool to a position in which both of the advance chamber and the retard chamber are communicated with the supply port so that a rotational phase of the camshaft relative to the crankshaft is held at a target rotational phase region.   
   
   
       2 . A valve timing controller according to  claim 1 , wherein
 the control valve is provided with an advance port and a retard port which respectively communicates with the advance chamber and the retard chamber, and   the spool is provided with an advance connecting passage which connects the advance port with the supply port, in which the advance check valve is arranged in such a manner that the operating fluid flow flowing from the advance port to the supply port is restricted, and a retard connecting passage which connects the retard port with the supply port, in which the retard check valve is arranged in such a manner that the operating fluid flow flowing from the retard port to the supply port is restricted.   
   
   
       3 . A valve timing controller according to  claim 2 , wherein
 the control valve moves the spool to a position in which the advance port communicates with the supply port in a case that the rotational phase of the camshaft relative to the crankshaft is advanced,   the control valve moves the spool to a position in which the retard port communicates with the supply port in a case that the rotational phase of the camshaft relative to the crankshaft is retarded, and   the control valve moves the spool to a position in which an opening degree of the advance port is restricted more than a case where the rotational phase of the camshaft is advanced and an opening degree of the retard port is restricted more than a case where the rotational phase of the camshaft is retarded in a case that the rotational phase of the camshaft relative to the crankshaft is held at the target rotational phase region.   
   
   
       4 . A valve timing controller according to  claim 1 , wherein
 the control valve is provided with a drain port through which the operating fluid is discharged,   the control valve moves the spool to a position in which the supply port communicates with the advance chamber and the drain port communicates with the retard chamber in a case that the rotational phase of the camshaft relative to the crankshaft is advanced, and   the control valve moves the spool to a position in which the supply port communicates with the retard chamber and the drain port communicates with the advance chamber in a case that the rotational phase of the camshaft relative to the crankshaft is retarded.