Valve opening/closing timing control apparatus

Abstract

A valve opening/closing timing control apparatus includes: a driving side rotating body rotating synchronously with a crankshaft of an internal combustion engine; a driven side rotating body included in the driving side rotating body and rotating integrally with a camshaft on a same axis as a rotation axis of the driving side rotating body; a hydraulic fluid control mechanism displacing a relative rotation phase between the driving side rotating body and the driven side rotating body by supplying a hydraulic fluid to one of an advance angle chamber and a retardation angle chamber; a lock mechanism; and first and second unlocking flow paths configured to communicate with the first pressure receiving surface. The lock mechanism includes a lock member including an engaging portion, a main body portion, and a first pressure receiving surface a biasing member, and a lock recess.

What is claimed is: 
     
         1 . A valve opening/closing timing control apparatus comprising:
 a driving side rotating body configured to rotate synchronously with a crankshaft of an internal combustion engine;   a driven side rotating body included in the driving side rotating body and configured to rotate integrally with a camshaft for opening or closing of a valve of the internal combustion engine on a same axis as a rotation axis of the driving side rotating body;   a hydraulic fluid control mechanism configured to displace a relative rotation phase between the driving side rotating body and the driven side rotating body by supplying a hydraulic fluid to one of an advance angle chamber and a retardation angle chamber, which are defined between the driving side rotating body and the driven side rotating body;   a lock mechanism including
 a lock member slidably inserted into a guide hole formed in one of the driving side rotating body and the driven side rotating body, and including
 an engaging portion, 
 a main body portion having a larger diameter than that of the engaging portion, and 
 a first pressure receiving surface formed in an annular shape on an end surface of the main body portion at an intermediate position between the engaging portion and the main body portion, 
 
 a biasing member configured to bias the lock member in a direction where the engaging portion on one end side of the lock member protrudes, and 
 a lock recess formed in a remaining one of the driving side rotating body and the driven side rotating body so as to allow the engaging portion to be fitted thereinto; 
   a first unlocking flow path configured to communicate with the first pressure receiving surface when the engaging portion is moved from a locking position where the engaging portion is fitted into the lock recess to a position at which the engaging portion is farther spaced apart from the lock recess than at a locking boundary position where the engaging portion is separated from the lock recess; and   a second unlocking flow path configured to communicate with the first pressure receiving surface when the engaging portion is at an unlocking position where the engaging portion is farther spaced apart from the lock recess than at the locking boundary position, and to be in non-communication state with the first pressure receiving surface as a flow path is closed by the main body portion when the engaging portion is at the locking boundary position.   
     
     
         2 . The valve opening/closing timing control apparatus according to  claim 1 ,
 wherein the lock recess includes a fittable region that extends in a displacement direction to enable displacement of the relative rotation phase in a state where the engaging portion is fitted into the lock recess, and a phase in which the engaging portion is fitted into one side end of the fittable region of the lock recess in the displacement direction is set to a locking phase, wherein a range of the fittable region under influence of the set locking phase is set to a sequence region, and in the sequence region, a drain flow path configured to discharge the hydraulic fluid communicates with the first unlocking flow path, and   an unlocking phase is set to be opposite to the locking phase on the basis of the sequence region in the fittable region, and in the unlocking phase, the first unlocking flow path and the drain flow path are in non-communication state with each other in a state where the engaging portion is fitted into the lock recess, and supply of the hydraulic fluid to the first unlocking flow path and the second unlocking flow path is enabled.   
     
     
         3 . The valve opening/closing timing control apparatus according to  claim 2 , further comprising:
 a phase sensor configured to detect the relative rotation phase; and   a lock shifting control unit configured to: start a first phase control so as to displace the relative rotation phase from a predetermined phase, which is opposite to the locking phase on the basis of the sequence region, to the locking phase; stop the displacement by the first phase control at a time when the phase sensor detects that the relative rotation phase exceeds the locking phase from the predetermined phase; start a second phase control so as to displace the relative rotation phase in a direction opposite to that in the first phase control; stop the displacement by the second phase control at a time when the phase sensor detects that the relative rotation phase reaches a predetermined phase in the sequence region; and then start a third phase control so as to displace the relative rotation phase toward the locking phase.   
     
     
         4 . The valve opening/closing timing control apparatus according to  claim 3 ,
 wherein, in the second phase control, when the relative rotation phase reaches the sequence region and the displacement is stopped, the stop is continued for a set time.   
     
     
         5 . The valve opening/closing timing control apparatus according to  claim 4 ,
 wherein a control form of the lock shifting control unit is set: to start a fourth phase control to stop the displacement when the phase sensor detects that the relative rotation phase exceeds the locking phase and is displaced to a predetermined phase after the third phase control, and thereafter displace the relative rotation phase in the same direction as the second phase control; to stop the fourth phase control at a time when the phase sensor detects that the relative rotation phase reaches a predetermined phase in the sequence region; to maintain the stopped state for a longer time than the set time; and then to perform a fifth phase control to displace the relative rotation phase toward the locking phase.   
     
     
         6 . The valve opening/closing timing control apparatus according to  claim 3 ,
 wherein an absolute value of a displacement speed in the second phase control is set to a smaller value than an absolute value of a displacement speed in the first phase control.   
     
     
         7 . The valve opening/closing timing control apparatus according to  claim 3 ,
 wherein in the second phase control, the displacement speed in the sequence region is reduced with respect to the displacement speed before reaching the sequence region.   
     
     
         8 . The valve opening/closing timing control apparatus according to  claim 3 ,
 wherein the lock shifting control unit performs a dither control to alternately and repeatedly supply the fluid into the advance angle chamber and the retardation angle chamber within a set time when the phase sensor detects that the relative rotation phase reaches the locking phase by the third phase control.   
     
     
         9 . The valve opening/closing timing control apparatus according to  claim 5 ,
 wherein the lock shifting control unit performs a dither control to alternately and repeatedly supply the fluid into the advance angle chamber and the retardation angle chamber within a set time when the phase sensor detects that the relative rotation phase reaches the locking phase by the third phase control.   
     
     
         10 . The valve opening/closing timing control apparatus according to  claim 2 ,
 wherein a locking assist flow path is formed to apply a pressure of the hydraulic fluid to the lock member in an engagement direction when the relative rotation phase is opposite to the sequence region on the basis of the locking phase.   
     
     
         11 . The valve opening/closing timing control apparatus according to  claim 2 , further comprising:
 an auxiliary lock mechanism including
 a lock body slidably inserted into a support hole portion formed in one of the driving side rotating body and the driven side rotating body, 
 a biasing body configured to bias a regulation end on one end side of the lock body so that the regulation end protrudes, and 
 an auxiliary lock recess formed in a remaining one of the driving side rotating body and the driven side rotating body so that the regulation end of the lock body is fitted into the auxiliary lock recess by biasing force of the biasing body, 
   wherein the auxiliary lock recess is formed in a region extending along the displacement direction of the relative rotation phase so that the displacement of the relative rotation phase is enabled in a state where the regulation end is fitted into the auxiliary lock recess, and   in a state where the relative rotation phase is in the locking phase, the lock body is disposed at a position at which the lock body inhibits the displacement of the relative rotation phase between both ends of the auxiliary lock recess in the displacement direction.   
     
     
         12 . The valve opening/closing timing control apparatus according to  claim 3 ,
 wherein one of the driving side rotating body and the driven side rotating body is configured as an inner rotor having the guide hole formed therein, and a remaining one of the driving side rotating body and the driven side rotating body is configured as an outer rotor having a pair of plates for fitting of the inner rotor therebetween, the lock recess being formed in one of the plates, and a communication portion being formed in a remaining one of the plates so as to enable communication between the guide hole and an external space,   as the relative rotation phase approaches the locking phase in the sequence region, a flow path area of the communication portion communicating with the external space is reduced and a flow path area of the drain flow path communicating with the first unlocking flow path is increased, and   in the second phase control, when the flow path area of the communication portion and the flow path area of the drain flow path reach 20% or more of that in a completely opened state, the displacement by the second phase control stops.   
     
     
         13 . The valve opening/closing timing control apparatus according to  claim 7 ,
 wherein the lock shifting control unit performs dither control to alternately and repeatedly supply the fluid to the advance angle chamber and the retardation angle chamber within a set time when the phase sensor detects that the relative rotation phase reaches the locking phase by the third phase control.   
     
     
         14 . The valve opening/closing timing control apparatus according to  claim 9 ,
 wherein the set time of the dither control performed after the fifth control is set to be longer than the set time of the dither control performed after the third control.   
     
     
         15 . The valve opening/closing timing control apparatus according to  claim 4 ,
 wherein, in the lock shifting control, a duration in which the relative rotation phase reaches the sequence region and the displacement is stopped is changed according to a hydraulic pressure and a number of revolutions of the internal combustion engine.