Valve timing adjusting apparatus

Abstract

A valve timing adjusting apparatus includes a housing, a vane rotor, a lock member, a resilient member, and a control unit. The housing includes a limitation groove, limitation stoppers, and a lock hole. When the lock member is received in the groove, the rotational phase is controlled within a predetermined range. When the lock member is fitted with the lock hole, the rotational phase is locked to a lock phase. The resilient member urges the lock member toward the limitation groove and the lock hole in the predetermined direction. The control unit controls a driving force that actuates the lock member in a direction opposite from the predetermined direction. The lock member has small and large diameter portions that are receivable in the lock hole.

1 . A valve timing adjusting apparatus for adjusting valve timing of a valve that is opened and closed by a camshaft through torque transmission from a crankshaft of an internal combustion engine, the valve timing adjusting apparatus comprising:
 a housing that is rotatable synchronously with the crankshaft, wherein:
 the housing includes a limitation groove, which extends in a circumferential direction of the housing, and which has first and second limitation stoppers at first and second circumferential end portions, respectively, of the limitation groove; 
 the housing includes a lock hole at the first circumferential end portion of the limitation groove; and 
 the lock hole is recessed further from the limitation groove in a predetermined direction; 
   a vane rotor that is rotatable synchronously with the camshaft, wherein:
 the vane rotor includes a vane that defines in the housing an advance chamber and a retard chamber that are arranged one after another in the circumferential direction; and 
 when working fluid is supplied to one of the advance chamber and the retard chamber, a rotational phase of the vane rotor is shifted relative to the housing in a corresponding one of an advance direction and a retard direction; 
   a lock member that is supported by the vane rotor, wherein:
 when the lock member is received in the limitation groove and is engageable with each of the first and second limitation stoppers, the rotational phase is controlled within a predetermined range; and 
 when the lock member is received in both of the limitation groove and the lock hole and is also fitted with the lock hole, the rotational phase is locked to a lock phase positioned between a full advance phase and a full retard phase; 
   a resilient member that urges the lock member toward the limitation groove and the lock hole in the predetermined direction; and   a control unit configured to control a driving force that actuates the lock member in a direction opposite from the predetermined direction, wherein:   the lock member has:
 a large-diameter portion having a first diameter; and 
 a small-diameter portion having a second diameter smaller than the first diameter and provided on one side of the large-diameter portion in the predetermined direction, where a bottom surface of the lock hole is located; and 
   the large-diameter portion and the small-diameter portion are receivable in the lock hole.   
   
   
       2 . The valve timing adjusting apparatus according to  claim 1 , wherein:
 the small-diameter portion is positioned on an end of the lock member in the predetermined direction; and   the lock member has an outer peripheral surface having a step-shaped profile.   
   
   
       3 . The valve timing adjusting apparatus according to  claim 1 , wherein:
 the small-diameter portion has a corner in the predetermined direction; and   the corner of the small-diameter portion is chamfered.   
   
   
       4 . The valve timing adjusting apparatus according to  claim 1 , wherein:
 the large-diameter portion of the lock member is fittable with the lock hole.   
   
   
       5 . The valve timing adjusting apparatus according to  claim 4 , wherein:
 the large-diameter portion has a corner in the predetermined direction; and   the corner of the large-diameter portion is chamfered.   
   
   
       6 . The valve timing adjusting apparatus according to  claim 1 , further comprising:
 a biasing member that biases the vane rotor in one of the advance direction and the retard direction of the rotational phase, wherein the first circumferential end portion is positioned on a side of the second circumferential end portion in the one of the advance direction and the retard direction of the rotational phase.   
   
   
       7 . The valve timing adjusting apparatus according to  claim 6 , wherein:
 the one of the advance direction and the retard direction of the rotational phase is the advance direction;   torque variations applied to the vane rotor through the camshaft bias the vane rotor in the retard direction of the rotational phase in average; and   when the rotational phase is positioned on a retard side of the lock phase, the biasing member biases the vane rotor in the advance direction.   
   
   
       8 . The valve timing adjusting apparatus according to  claim 7 , wherein:
 the control unit removes the driving force when the internal combustion engine is stopped.   
   
   
       9 . The valve timing adjusting apparatus according to  claim 1 , wherein:
 the housing further includes a regulation groove, which extends in the circumferential direction, and which defines a regulation stopper at one circumferential end portion of the regulation groove; and   the resilient member serves as a lock resilient member, the valve timing adjusting apparatus further comprising:   a regulation member that is supported by the vane rotor, wherein the regulation member is receivable in the regulation groove and is engageable with the regulation stopper such that the rotational phase is controlled to a certain phase within the predetermined range; and   a regulation resilient member that urges the regulation member toward the regulation groove in the predetermined direction, wherein:   the control unit also controls a regulation driving force that drives the regulation member in the direction opposite from the predetermined direction.   
   
   
       10 . The valve timing adjusting apparatus according to  claim 9 , wherein:
 the regulation member has:
 a large-diameter portion having a first diameter; and 
 a small-diameter portion having a second diameter smaller than the first diameter and provided on one side of the large-diameter portion where a bottom surface of the regulation groove is located; and 
   the large-diameter portion and the small-diameter portion are receivable in the regulation groove.   
   
   
       11 . The valve timing adjusting apparatus according to  claim 10 , wherein:
 the small-diameter portion is provided on an end of the regulation member in the predetermined direction; and   the regulation member has an outer peripheral surface having a step-shaped profile.   
   
   
       12 . A valve timing adjusting apparatus for adjusting valve timing of a valve that is opened and closed by a camshaft through torque transmission from a crankshaft of an internal combustion engine, the valve timing adjusting apparatus comprising:
 a housing that is rotatable synchronously with the crankshaft, wherein:
 the housing includes a limitation groove, which extends in a circumferential direction of the housing, and which has first and second limitation stoppers at first and second circumferential end portions, respectively, of the limitation groove; 
 the housing includes a lock hole at the first circumferential end portion of the limitation groove; and 
 the lock hole is recessed further from the limitation groove in an axial direction of the housing; 
   a vane rotor that is rotatable synchronously with the camshaft, wherein:
 the vane rotor includes a vane that defines in the housing an advance chamber and a retard chamber that are arranged one after another in the circumferential direction; and 
 when working fluid is supplied to one of the advance chamber and the retard chamber, a rotational phase of the vane rotor is shifted relative to the housing in a corresponding one of an advance direction and a retard direction; and 
   a lock member that is supported by the vane rotor, wherein:
 the lock member has:
 a large-diameter portion having a first diameter; and 
 a small-diameter portion having a second diameter smaller than the first diameter and provided on one axial side of the large-diameter portion where an axial bottom surface of the lock hole is located; and 
 
 the lock member is axially displaceable from an initial position to first and second positions in the axial direction; 
 when the lock member is placed in the first position, the large-diameter portion of the lock member is displaceable circumferentially within the limitation groove between the first and second limitation stoppers such that the rotational phase is controlled within a predetermined range that is positioned between a full advance phase and a full retard phase of the vane rotor; and 
 when the lock member is placed in the second position, the large-diameter portion is fitted with the lock hole such that the rotational phase is locked to a lock phase positioned within the predetermined range. 
   
   
   
       13 . The valve timing adjusting apparatus according to  claim 12 , further comprising:
 a resilient member that urges the lock member toward the limitation groove and the lock hole in the axial direction; and   a control unit configured to control a driving force that actuates the lock member in a direction away from the limitation groove and the lock hole.   
   
   
       14 . The valve timing adjusting apparatus according to  claim 12 , further comprising:
 a biasing member that biases the vane rotor in one of the advance direction and the retard direction of the rotational phase, wherein the first circumferential end portion is positioned on a side of the second circumferential end portion in the one of the advance direction and the retard direction of the rotational phase.   
   
   
       15 . The valve timing adjusting apparatus according to  claim 12 , further comprising:
 a regulation member that is supported by the vane rotor, wherein the regulation member is receivable in the regulation groove and is engageable with the regulation stopper such that the rotational phase is controlled to a certain phase within the predetermined range; and   a regulation resilient member that urges the regulation member toward the regulation groove in the axial direction, wherein:   the control unit also controls a regulation driving force that drives the regulation member in a direction away from the regulation groove.