Patent Publication Number: US-9410454-B2

Title: Valve opening/closing timing control device

Description:
TECHNICAL FIELD 
     The present invention relates to a valve opening/closing timing control device that controls a relative rotation phase of a driven rotating body with respect to a driving rotating body that rotates synchronously with a crankshaft of an internal combustion engine. 
     BACKGROUND ART 
     In recent years, valve opening/closing timing control devices that make it possible to change the opening/closing timing of an intake valve and an exhaust valve in accordance with the operation status of an internal combustion engine (hereinafter referred to as an “engine” as well) have been put to practical use. These valve opening/closing timing control devices have a mechanism that, for example, by changing the relative rotation phase of the driven rotating body with respect to the rotation of the driving rotating body (hereinafter referred to as simply “relative rotation phase”) by means of an engine operation, changes the opening/closing timing of an intake/exhaust valve that is opened and closed accompanying the rotation of the driven rotating body. 
     In general, the optimal opening/closing timing of the intake/exhaust valve differs according to the operation state of the engine, such as the state in which the engine is started, and the state in which the vehicle is traveling. By constraining the relative rotation phase to an intermediate lock phase between the maximum retard phase and the maximum advance phase when starting the engine, the opening/closing timing of the intake/exhaust valve that is optimal for starting the engine is realized, and a case in which a knocking sound is generated due to a partition of a fluid pressure chamber formed by the driving rotating body and the driven rotating body swinging is suppressed. For this reason, it is desired that the relative rotation phase is constrained to the intermediate lock phase before the engine is stopped. The stopping of the engine also includes idling stops in which the engine is stopped for a short amount of time at an intersection or the like so as to suppress the discharge of exhaust gas or the consumption of gasoline. 
     Patent Document 1 discloses a valve timing adjustment device that can reliably perform locking when a lock pin is to be locked in an intermediate phase between the maximum advance phase and the maximum retard phase. With this valve timing adjustment device, a control valve is configured to connect an advancing port and a lock port to a main supply port and a discharge opening respectively by moving to a first region, and to connect both the advancing port and the lock port to the main supply port by moving to a second region that is shifted away from the first region in a second direction. The first region is a lock region for locking the rotation phase in a restricted phase using a first main restricting member. Furthermore, the first region has a reduction region in which an advance supply flow amount to be supplied to an advancing chamber by connecting the advancing port in communication with the advancing chamber to the main supply port is reduced to a flow amount that is smaller than the flow amount at the moving end in the first direction. Accordingly, in the constricted region, the speed at which a vane rotor rotates to the advance side is a slower speed that corresponds to the flow amount controlled to be a smaller amount. Furthermore, when the phase of the vane rotor gradually changes to the advance side in this way, the lock port and the discharge opening are connected so that working oil is discharged from the lock chamber. Accordingly, locking of the rotation phase that accompanies the flow of the working oil from the lock chamber can be performed reliably due to the phase of the vane rotor gradually changing to the advance side. 
     PRIOR ART DOCUMENTS 
     Patent Documents 
     Patent Document 1: JP 2012-140968A 
     DISCLOSURE OF THE INVENTION 
     Problem to be Solved by the Invention 
     Recently, in vehicles having idling stop functions, in order to increase fuel efficiency, instructions for stopping the engine are given at an earlier timing. That is, a vehicle with an idling stop function is conventionally given an instruction to stop the engine after the vehicle speed reaches zero, whereas recently, instructions for stopping the engine have been given at a time of falling below a predetermined vehicle speed (e.g., 10 km/h). However, in order to suitably re-start the engine, the engine has to be stopped after the relative rotation phase has been constrained to an intermediate lock phase. For this reason, the relative rotation phase needs to be constrained to the intermediate lock phase in a short amount of time after the engine stop instruction has been given. 
     With the valve timing adjustment device disclosed in Patent Document 1, a configuration is used in which the speed at which the vane rotor rotates to the advance side is decreased in order to reliably lock the rotation phase in the intermediate lock phase. For this reason, in the case where the valve timing adjustment device is applied to a vehicle with an idling stop function, there is a risk that constraint to the intermediate lock phase will not be possible in a short amount of time. 
     Accordingly, there has been demand to provide a valve opening/closing timing control device that can change the relative rotation phase in a short amount of time so as to constrain it to the intermediate lock phase. 
     Means for Solving Problem 
     In order to solve the above-described problem, a characteristic configuration of a valve opening/closing timing control device according to the present invention lies in including: a driving rotating body that rotates synchronously with a driving shaft of an internal combustion engine; a driven rotating body that is arranged inside of the driving rotating body coaxially with an axis of the driving rotating body, and rotates integrally with a camshaft for opening/closing a valve of the internal combustion engine; a fluid pressure chamber defined between the driving rotating body and the driven rotating body; an advancing chamber and a retarding chamber formed by partitioning the fluid pressure chamber using a partition provided on at least one of the driving rotating body and the driven rotating body; an intermediate locking mechanism capable of, with supply/discharge of a working fluid, selectively switching between a locked state in which a relative rotation phase of the driven rotating body with respect to the driving rotating body is constrained to an intermediate lock phase between a maximum advance phase and a maximum retard phase, and an unlocked state in which the constraint to the intermediate lock phase is released; an advancing channel that allows passage of the working fluid to be supplied to or discharged from the advancing chamber; a retarding channel that allows passage of the working fluid to be supplied to or discharged from the retarding chamber; and at least one electromagnetic valve that changes a position of a spool by changing an electricity supply amount, and controls the supply and discharge of the working fluid to/from the advancing chamber, the retarding chamber, and the intermediate lock mechanism, wherein when in a lock transition mode in which the electromagnetic valve is controlled such that the working fluid is discharged from the intermediate lock mechanism, the working fluid is supplied to one of the advancing chamber and the retarding chamber, and the working fluid is discharged from the other one, maximum flow amounts of the working fluid that flows through the advancing channel and the retarding channel are greater than maximum flow amounts of the working fluid that flows through the advancing channel and the retarding channel when in a phase changeable mode in which the electromagnetic valve is controlled such that the working fluid is supplied to the intermediate lock mechanism. 
     If the flow amount of the working fluid that flows through the advancing channel is increased, the supply/discharge of the working fluid to/from the advancing chamber will be performed more rapidly, and if the flow amount of the working fluid that flows through the retarding channel is increased, the supply/discharge of the working fluid to/from the retarding chamber will be performed more rapidly. Also, if the supply/discharge of the working fluid to/from the advancing chamber or the retarding chamber is performed more rapidly, the speed at which the relative rotation phase changes in the advance direction or the retard direction will increase. Accordingly, if such a configuration is used, the speed at which the relative rotation phase changes in the advance direction or the retard direction will be greater in the lock transition mode in which the working fluid is discharged from the intermediate lock mechanism than in the phase changeable mode in which the working fluid is supplied to the intermediate lock mechanism. Accordingly, if the electromagnetic valve is controlled to be in the lock transition mode when the relative rotation phase is in the vicinity of the maximum retard phase or the maximum advance phase, for example, the relative rotation phase changes at a high speed, and it is possible to reach the state of being locked in the intermediate lock phase in a short amount of time. 
     With the valve opening/closing timing control device of the present invention, it is preferable that when in the lock transition mode, the flow amount of the working fluid that flows through the advancing channel and the retarding channel increases as the spool of the electromagnetic valve approaches an end of a range of motion of the spool. 
     When the spool is located at an end of its range of motion, the amount of electricity supplied to the solenoid that moves the spool is 0 or the maximum. In other words, when the amount of electricity supplied to the solenoid is 0 or the maximum, the supply/discharge of the working fluid to/from the advancing chamber or the retarding chamber is performed rapidly, and the speed at which the relative rotation phase changes in the advance direction or the retard direction reaches its maximum. Accordingly, if such a configuration is used, there is no need to finely control the electricity supply amount when it is desired that the relative rotation phase is changed at a high speed. In other words, by setting the electricity supply amount to 0 or the maximum, the relative rotation phase can be changed at a high speed, and the state of being locked in the intermediate lock phase can be reached in a short amount of time. 
     With the valve opening/closing timing control device of the present invention, it is preferable that in the lock transition mode, the relative rotation phase is configured to be changeable in both an advance direction and a retard direction, in the lock transition mode, the working fluid flows through a first discharge channel so as to be discharged from the intermediate lock mechanism while the relative rotation phase changes in the advance direction when the spool of the electromagnetic valve is at one end of the range of motion of the spool, and the working fluid flows through a second discharge channel so as to be discharged from the intermediate lock mechanism while the relative rotation phase changes in the retard direction when the spool is at the other end of the range of motion, if a retard change speed, which is a speed of the driven rotating body when the relative rotation phase changes in the retard direction, is greater than an advance change speed, which is a speed of the driven rotating body when the relative rotation phase changes in the advance direction, a flow amount of the working fluid that flows through the second discharge channel is greater than a flow amount of the working fluid that flows through the first discharge channel by at least a ratio of the retard change speed to the advance change speed, and if the advance change speed is greater than the retard change speed, the flow amount of the working fluid that flows through the first discharge channel is greater than the flow amount of the working fluid that flows through the second discharge channel by at least a ratio of the advance change speed to the retard change speed. 
     In order to realize the state of being locked in the intermediate lock phase in a short amount of time by changing the relative rotation phase at a high speed, it is necessary to discharge the working fluid from the intermediate lock mechanism in a short amount of time. In view of this, if such a configuration is used, the flow amount of the working fluid discharged from the intermediate lock mechanism when the relative rotation phase changes in the direction in which it changes at a higher speed can be made greater than the flow amount of the working fluid discharged from the intermediate lock mechanism when the relative rotation phase changes in the direction in which it changes at a lower speed. As a result, the state of being locked in the intermediate lock phase can be realized reliably also when the relative rotation phase is constrained at a high speed. 
     With the valve opening/closing timing control device of the present invention, it is preferable that in the phase changeable mode, the flow amount of the working fluid when the working fluid is supplied to the intermediate lock mechanism while the relative rotation phase is held is greater than the flow amount of the working fluid when the working fluid is supplied to the intermediate lock mechanism while the relative rotation phase is changed. 
     One significant problem that can occur when the intermediate lock mechanism is in the unlocked state is that of unintentionally entering the locked state. When the locked state is entered, change in the relative rotation phase is restricted, and therefore there is a risk that it will not be possible to change to a desired relative rotation phase. This kind of unintentional locked state occurs when oil pressure pulsation occurs in the working fluid accompanying variations in the torque of the camshaft that occur due to the rotation of the cams when the relative rotation phase is held in the intermediate lock phase, and the lower limit value of the oil pressure pulsation falls below the oil pressure at which the unlocked state can be maintained. 
     In view of this, if such a configuration is used, pressure loss caused by the working fluid acting on the intermediate lock mechanism when the relative rotation phase is held in the intermediate lock phase reaches its minimum. As a result, the lower limit value of the oil pressure pulsation can be increased, and the occurrence of an unintended locked state can be suppressed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a vertical cross-sectional view showing a configuration of a valve opening/closing timing control device according to a first embodiment. 
         FIG. 2  is a cross-sectional view taken along line II-II in  FIG. 1 . 
         FIG. 3  is a diagram showing a state in which working oil flows through channels due to the action of an OCV. 
         FIG. 4  is a graph showing change in the flow amounts of the working oil supplied to and discharged from an advancing chamber, a retarding chamber, and an intermediate lock mechanism when the position of a spool is changed. 
         FIG. 5  is an enlarged cross-sectional view showing an active state of the OCV in W1. 
         FIG. 6  is an enlarged cross-sectional view showing an active state of the OCV in W2. 
         FIG. 7  is an enlarged cross-sectional view showing an active state of the OCV in W3. 
         FIG. 8  is an enlarged cross-sectional view showing an active state of the OCV in W4. 
         FIG. 9  is an enlarged cross-sectional view showing an active state of the OCV in W4E. 
         FIG. 10  is a vertical cross-sectional view showing a configuration of a valve opening/closing timing control device according to a second embodiment. 
         FIG. 11  is a cross-sectional view taken along line XI-XI in  FIG. 10 . 
         FIG. 12  is a diagram showing a state in which working oil flows through channels due to the action of the OCV. 
         FIG. 13  is a graph showing change in the flow amounts of working oil supplied to and discharged from the advancing chamber, retarding chamber, and intermediate lock mechanism when the position of the spool is changed. 
         FIG. 14  is an expanded cross-sectional view showing an active state of the OCV in W1. 
         FIG. 15  is an expanded cross-sectional view showing an active state of the OCV in W2. 
         FIG. 16  is an expanded cross-sectional view showing an active state of the OCV in W3. 
         FIG. 17  is an expanded cross-sectional view showing an active state of the OCV in W4. 
         FIG. 18  is an expanded cross-sectional view showing an active state of the OCV in W5. 
         FIG. 19  is an expanded cross-sectional view showing an active state of the OCV in W5. 
         FIG. 20  is a vertical cross-sectional view showing a configuration of a valve opening/closing timing control device according to another embodiment. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     1. First Embodiment 
     Hereinafter, a first embodiment in which the present invention is applied to a valve opening/closing timing control device for an intake valve in an automobile engine (hereinafter simply referred to as an “engine E”) will be described in detail with reference to the drawings. In the following description of the embodiment, the engine E is an example of an internal combustion engine. 
     Overall Configuration 
     As shown in  FIG. 1 , a valve opening/closing timing control device  10  includes a housing  1  that rotates synchronously with a crankshaft C, and an inner rotor  2  that is disposed coaxially on axis X of the housing  1  inside of the housing  1  and rotates integrally with a camshaft  101  for opening/closing valves of the engine E. The camshaft  101  is a rotation shaft for cams  104 , which control the opening/closing of intake valves  103  of the engine E, and rotates synchronously with the inner rotor  2  and a fixing bolt  5 . The camshaft  101  is rotatably installed on a cylinder head of the engine E. Note that the crankshaft C is an example of a driving shaft, the housing  1  is an example of a driving rotating body, and the inner rotor  2  is an example of a driven rotating body. 
     A male screw  5   b  is formed on an end near the camshaft  101  of the fixing bolt  5 . In a state in which the housing  1  and the inner rotor  2  are combined, the fixing bolt  5  is inserted into the middle and a male screw  5   b  of the fixing bolt  5  is screwed into a female screw  101   a  of the camshaft  101 , and thereby the fixing bolt  5  is fixed to the camshaft  101  and the inner rotor  2  and the camshaft  101  are also fixed. 
     The housing  1  is constituted by installing, using a fastening bolt  16 , a front plate  11  disposed on the side opposite to the side to which the camshaft  101  is connected, an outer rotor  12  fitted onto the inner rotor  2 , and a rear plate  13  that integrally includes a timing sprocket  15  and is disposed on a side at which the camshaft  101  is connected. The inner rotor  2  is housed in the housing  1 , and later-described fluid pressure chambers  4  are formed between the inner rotor  2  and the outer rotor  12 . The inner rotor  2  and the outer rotor  12  are constituted so as to be able to rotate relative to each other about the axis X. Note that instead of the timing sprocket  15  being included in the rear plate  13 , the timing sprocket  15  may be included in the outer circumferential portion of the outer rotor  12 . 
     A return spring  70  that causes a biasing force to act in a direction of rotation centered about the axis X is included between the housing  1  and the camshaft  101 . The return spring  70  has a function of causing a biasing force to act until the relative rotation phase of the inner rotor  2  with respect to the housing  1  (hereinafter simply referred to as the “relative rotation phase”) reaches a predetermined relative rotation phase that is on the advance side from the maximum retard state (in the present embodiment, a later-described intermediate lock phase P), and not causing the biasing force to act in a range in which the relative rotation phase is on the advance side of the predetermined rotation phase. For example, a torsion spring or a spiral spring is used. Note that the return spring  70  may be disposed between the housing  1  and the inner rotor  2 . 
     When the crankshaft C is driven so as to rotate, the rotation driving force is transferred to the timing sprocket  15  via a power transfer member  102 , and the housing  1  is driven so as to rotate in a rotation direction S shown in  FIG. 2 . Accompanying the rotation driving of the housing  1 , the inner rotor  2  is driven so as to rotate in the rotation direction S so that the camshaft  101  rotates, and the cams  104  provided on the camshaft  101  press down the intake valves  103  of the engine E so as to open them. 
     As shown in  FIG. 2 , the fluid pressure chambers  4  are formed between the inner rotor  2  and the outer rotor  12  due to three protruding portions  14  that protrude inward in the radial direction and come into contact with the outer circumferential surface of the inner rotor  2  being formed apart from each other in the rotation direction S in the outer rotor  12 . The protruding portions  14  also function as shoes on the outer circumferential surface of the inner rotor  2 . Protruding portions  21  that come into contact with the inner circumferential surface of the outer rotor  12  are formed at portions on the outer circumferential surface of the inner rotor  2  which oppose the fluid pressure chambers  4 . The fluid pressure chambers  4  are each divided into an advancing chamber  41  and a retarding chamber  42  by a protruding portion  21 . Note that in the present embodiment, three fluid pressure chambers  4  are included, but there is no limitation to this. 
     Working oil (an example of working fluid) is supplied to or discharged from the advancing chambers  41  and the retarding chambers  42 , or the supply/discharge thereof is blocked, and thereby the oil pressure of the working oil acts on the protruding portions  21 , and the relative rotation phase is changed in the advance direction or the retard direction using the oil pressure, or is held at a certain phase. The advance direction is a direction in which the volume of the advancing chambers  41  increases, and is the direction indicated by arrow S 1  in  FIG. 2 . The retard direction is a direction in which the volume of the retarding chambers  42  increases, and is the direction indicated by arrow S 2  in  FIG. 2 . The relative rotation phase when the protruding portions  21  have reached their moving ends (ends of swinging centered about the axis X) in the advance direction S 1  is referred to as the maximum advance phase, and the relative rotation phase when the protruding portions  21  have reached their moving ends (ends of swinging centered about the axis X) in the retard direction S 2  is referred to as the maximum retard phase. Note that the maximum advance phase is a concept that includes not only the moving ends in the advance direction S 1  of the protruding portions  21 , but also the vicinities thereof. Similarly, the maximum retard phase is a concept that includes not only the moving ends in the retard direction S 2  of the protruding portions  21 , but also the vicinities thereof. 
     As shown in  FIG. 2 , advancing channels  43  that are in communication with the advancing chambers  41 , retarding channels  44  that are in communication with the retarding chambers  42 , and unlocking channels  45  through which working oil that is to be supplied to and discharged from a later-described intermediate lock mechanism  8  flows are formed in the inner rotor  2 . As shown in  FIG. 1 , in the valve opening/closing timing control device  10 , lubricating oil that is stored in an oil pan  61  of the engine E is used as the working oil, and the working oil is supplied to the advancing chambers  41 , the retarding chambers  42 , and the intermediate lock mechanism  8 . 
     Intermediate Lock Mechanism 
     The valve opening/closing timing control device  10  includes an intermediate lock mechanism  8  that constrains the relative rotation phase to an intermediate lock phase P between the maximum advance phase and the maximum retard phase by constraining change in the relative rotation phase of the inner rotor  2  with respect to the housing  1 . Due to the engine E being started in a state where the relative rotation phase is constrained to the intermediate lock phase P, even in a situation where the oil pressure of the working oil immediately after the engine start operation is not stable, the rotation phase of the camshaft  101  with respect to the rotation phase of the crankshaft C is maintained appropriately, and stable rotation of the engine E can be realized. 
     As shown in  FIG. 2 , the intermediate lock mechanism  8  is constituted by a first lock member  81 , a first spring  82 , a second lock member  83 , a second spring  84 , a first recessed portion  85 , and a second recessed portion  86 . 
     The first lock member  81  and the second lock member  83  are constituted by plate-shaped members, and are movably supported on the outer rotor  12  such that they can be brought toward and separated from the inner rotor  2  in an orientation parallel to the axis X. The first lock member  81  moves toward the inner rotor  2  due to the biasing force of the first spring  82 , and the second lock member  83  moves toward the inner rotor  2  due to the biasing force of the second spring  84 . 
     The first recessed portion  85  is defined in a groove shape along the direction of the axis X in the outer circumference of the inner rotor  2 . The first recessed portion  85  is such that a shallow groove and a deep groove are formed continuously in the circumferential direction toward the retard direction S 2 . The groove width of the shallow groove is larger than the thickness of the first lock member  81 , and the groove width of the deep groove is equivalent to that of the shallow groove and is larger than the thickness of the first lock member  81 . The second recessed portion  86  is defined in a groove shape along the direction of the axis X in the outer circumference of the inner rotor  2 . The second recessed portion  86  is such that a shallow groove and a deep groove are formed continuously in the circumferential direction toward the retard direction S 2 . The groove width of the shallow groove is about the same as the thickness of the second lock member  83 , and the groove width of the deep groove is sufficiently larger than the thickness of the second lock member  83  and is larger than the groove width of the deep groove of the first recessed portion  85 . 
     As shown in  FIG. 2 , with the intermediate lock phase P in a state in which no working oil has been supplied to the first recessed portion  85  and the second recessed portion  86 , after moving toward the inner rotor  2  due to the biasing force of the first spring  82 , the first lock member  81  fits into the first recessed portion  85 , and the first lock member  81  comes into contact with the end in the advance direction S 1  of the deep groove of the first recessed portion  85  so as to restrict the inner rotor  2  from changing in the retard direction S 2 . Also, after moving toward the inner rotor  2  due to the biasing force of the second spring  84 , the second lock member  83  fits into the second recessed portion  86  and the second lock member  83  comes into contact with the end in the retard direction S 2  of the deep groove of the second recessed portion  86  so as to restrict the inner rotor  2  from changing in the advance direction S 1 . Thus, the relative rotation phase is constrained to the intermediate lock phase P by simultaneously restricting change in the advance direction S 1  and the retard direction S 2  of the inner rotor  2 . This is the locked state. 
     The unlocking channels  45  are connected to the bottom surfaces of the deep groove of the first recessed portion  85  and the deep groove of the second recessed portion  86 , and when the working oil flows through the unlocking channels  45  so as to be supplied to the first recessed portion  85  and the second recessed portion  86  when in the locked state, the first lock member  81  and the second lock member  83  receive the oil pressure of the working oil. If the oil pressure exceeds the biasing force of the first spring  82  and the second spring  84 , the first lock member  81  and the second lock member  83  separate from the first recessed portion  85  and the second recessed portion  86  respectively, and the unlocked state is entered. Also, the working oil, which is in the first recessed portion  85  and the second recessed portion  86  in the unlocked state, flows through the unlocking channels  45  and can be discharged to the outside of the valve opening/closing timing control device  10 . Thus, the unlocking channels  45  allow passage of working fluid that is to be supplied to or discharged from the first recessed portion  85  and the second recessed portion  86 . 
     OCV 
     As shown in  FIG. 1 , in the present embodiment, an OCV (oil control valve)  51  is disposed inside of the inner rotor  2 , coaxially with the axis X. The OCV  51  is an example of an electromagnetic valve. The OCV  51  is configured to include a spool  52 , a first valve spring  53   a  that biases the spool  52 , and an electromagnetic solenoid  54  that drives the spool  52  due to the electricity supply amount being changed. Note that the electromagnetic solenoid  54  is a known technology and therefore will not be described in detail here. 
     The spool  52  is accommodated in an accommodation space  5   a , which is a hole with a circular cross-section that is formed in the direction of the axis X starting from a head portion  5   c , which is the end that is further from the camshaft  101  of the fixing bolt  5 , and the spool  52  can slide in the direction of the axis X inside of the accommodation space  5   a . The spool  52  also has a main discharge channel  52   b , which is a bottomed hole with a circular cross-section along the direction of the axis X. The inner diameter of the main discharge channel  52   b  is larger near the entrance than in the interior, and a level difference is formed therein. 
     The first valve spring  53   a  is provided deep inside of the accommodation space  5   a , and normally biases the spool  52  in the direction of the electromagnetic solenoid  54  (the leftward direction in  FIG. 1 ). The spool  52  is prevented from popping out of the accommodation space  5   a  by a stopper  55  attached to the accommodation space  5   a . The level difference formed in the main discharge channel  52   b  holds one end of the first valve spring  53   a . A partition  5   d  is inserted at the border between the accommodation space  5   a  and a third supply portion  47   c , which is a bottomed hole with a smaller inner diameter and is formed continuously with the accommodation space  5   a . The partition  5   d  holds the other end of the first valve spring  53   a . When electricity is supplied to the electromagnetic solenoid  54 , a push pin  54   a  provided in the electromagnetic solenoid  54  presses the end  52   a  of the spool  52 . As a result, the spool  52  slides in the direction of the camshaft  101  against the biasing force of the first valve spring  53   a . The OCV  51  is configured to be able to adjust the position of the spool  52  by changing the amount of electricity supplied to the electromagnetic solenoid  54  from 0 to the maximum. The amount of electricity supplied to the electromagnetic solenoid  54  is controlled by an ECU (electronic control unit) (not shown). 
     According to the position of the spool  52 , the OCV  51  switches between the supply of working oil to the advancing chambers  41  and the retarding chambers  42 , discharge thereof, and holding thereof, and performs switching between the supply of working oil to the intermediate lock mechanism  8  and the discharge thereof.  FIG. 3  shows an active configuration of the OCV  51  when the position of the spool  52  is changed to W1 to W5 according to the amount of electricity supplied to the electromagnetic solenoid  54 . 
     Oil Channel Configuration 
     As shown in  FIG. 1 , the working oil stored in the oil pan  61  is pumped by a mechanical oil pump  62  that is driven by the rotation driving force of the crankshaft C being transferred thereto, and the working oil flows through a later-described supply channel  47 . Then, after flowing through the supply channel  47 , the working oil is supplied to the advancing channels  43 , the retarding channels  44 , and the unlocking channels  45  via the OCV  51 . 
     As shown in  FIG. 1  and  FIGS. 5 to 9 , the advancing channels  43 , which are connected to the advancing chambers  41 , are each constituted by a first advancing portion  43   a , which is a through hole formed in the fixing bolt  5  and a second advancing portion  43   b  that is connected to the first advancing portion  43   a  and is formed in the inner rotor  2 . The retarding channels  44 , which are connected to the retarding chambers  42 , are each constituted by a first retarding portion  44   a , which is a through hole formed in the fixing bolt  5 , and a second retarding portion  44   b  that is connected to the first retarding portion  44   a  and is formed in the inner rotor  2 . The unlocking channels  45 , which are connected to the first recessed portion  85  and the second recessed portion  86 , are each constituted by a first unlocking portion  45   a , which is a through hole formed in the fixing bolt  5 , and a second unlocking portion  45   b  that is connected to the first unlocking portion  45   a  and is formed in the inner rotor  2 . 
     A supply channel  47  is constituted by a first supply portion  47   a  formed in the camshaft  101 , a second supply portion  47   b , which is a space between the camshaft  101  and the fixing bolt  5 , a third supply portion  47   c  formed in the fixing bolt  5 , a fourth supply portion  47   d  formed around the fixing bolt  5 , a fifth supply portion  47   e  formed in the inner rotor  2 , and two sixth supply portions  47   f  formed at different locations in the direction of the axis X of the fixing bolt  5 , and the channels are connected in the stated order. 
     The third supply portion  47   c  is constituted by a bottomed hole formed in the fixing bolt  5  in the direction of the axis X, and multiple holes penetrating to the outside at two different locations in the axis X direction in the bottomed hole. A check valve  48  is included in the bottomed hole, and the check valve  48  is biased in the direction of closing the bottomed hole of the third supply portion  47   c  by a second valve spring  53   b , which is held by the partition  5   d  and the check valve  48 . 
     The fifth supply portion  47   e  is constituted by a channel that is formed in the fixing bolt  5  in the direction of the axis X and whose ends are closed, and three ring-shaped grooves formed inwardly in the diameter direction from the channel to the inner circumferential surface at three different locations in the axis X direction. One of the three ring-shaped grooves opposes the fourth supply portion  47   d  and the remaining two ring-shaped grooves respectively oppose separate sixth supply portions  47   f.    
     As shown in order starting from the left in  FIG. 5 , a sixth supply portion  47   f , the first unlocking portion  45   a , the first advancing portion  43   a , a sixth supply portion  47   f , and the first retarding portion  44   a , which are through holes formed in the fixing bolt  5 , are respectively connected to the first ring-shaped groove  47   g , the second ring-shaped groove  47   h , the third ring-shaped groove  47   i , the fourth ring-shaped groove  47   j , and the fifth ring-shaped groove  47   k , which are ring-shaped grooves formed in the inner circumferential surface opposing the accommodation space  5   a  of the fixing bolt  5 . 
     A seventh ring-shaped groove  52   c  and an eighth ring-shaped groove  52   d  that supply the working oil that flows through the supply channel  47  to one of the advancing channels  43 , the retarding channels  44 , and the unlocking channels  45  are formed in the outer circumferential surface of the spool  52 . Furthermore, a first through hole  52   e  and a second through hole  52   f  for discharging the working oil that flows through the advancing channels  43 , the retarding channels  44 , and the unlocking channels  45  to the main discharge channel  52   b  are formed in the spool  52 . The first through hole  52   e  and the second through hole  52   f  are respectively connected to a ninth ring-shaped groove  52   h  and a tenth ring-shaped groove  52   i , which are ring-shaped grooves formed in the outer circumferential surface of the spool  52 . Furthermore, third through holes  52   g  that discharge the working oil that flows through the main discharge channel  52   b  to the outside of the valve opening/closing timing control device  10  are formed. 
     Operation of OCV 
     (1) W1 State 
     As shown in  FIG. 5 , if electricity is not supplied to the electromagnetic solenoid  54  (electricity supply amount is 0), the OCV  51  is in the W1 state shown in  FIG. 3 , and the spool  52  comes into contact with the stopper  55  and is located leftmost due to the biasing force of the first valve spring  53   a . If the working oil is supplied to the supply channel  47  in this state, the working oil will flow through the first supply portion  47   a , the second supply portion  47   b , and the third supply portion  47   c . If the oil pressure acting on the check valve  48  exceeds the biasing force of the second valve spring  53   b  in the third supply portion  47   c , the check valve  48  opens. Then, the working oil passes through the fourth supply portion  47   d , the fifth supply portion  47   e , and the sixth supply portion  47   f  so as to reach the seventh ring-shaped groove  52   c  via the first ring-shaped groove  47   g  and to reach the eighth ring-shaped groove  52   d  via the fourth ring-shaped groove  47   j.    
     The seventh ring-shaped groove  52   c  is not connected to any of the channels, and thus no more working oil flows thereto. The eighth ring-shaped groove  52   d  is connected to the advancing channels  43  via the third ring-shaped groove  47   i , and therefore the working oil flows through the advancing channels  43  so as to be supplied to the advancing chambers  41 . In other words, the advancing channels  43  are in the supply state. On the other hand, the retarding channels  44  are connected to the second through hole  52   f  via the fifth ring-shaped groove  47   k  and the tenth ring-shaped groove  52   i , and the unlocking channels  45  are connected to the first through hole  52   e  via the second ring-shaped groove  47   h  and the ninth ring-shaped groove  52   h . For this reason, the working oil in the retarding chambers  42 , the first recessed portion  85 , and the second recessed portion  86  is discharged from the main discharge channel  52   b  to the outside of the valve opening/closing timing control device  10  through the third through holes  52   g . In other words, the retarding channels  44  and the unlocking channels  45  are all in the drain state. Accordingly, as shown in  FIG. 3 , the W1 state is a state in which working oil is discharged from the intermediate lock mechanism  8  (first recessed portion  85 , second recessed portion  86 ) and the retarding chambers  42  and the working oil is supplied to the advancing chambers  41  so that the relative rotation phase changes in the advance direction S 1 , and this corresponds to “locking in the intermediate lock phase P by means of an advancing action”. The W1 state corresponds to a lock transition mode in the present invention. 
     If the oil pressure of the working oil is constant in the W1 state, the flow amount of the working oil that flows through the advancing channels  43  to be supplied to the advancing chambers  41  is determined by the smaller of an area of opposition between the third ring-shaped groove  47   i  and the eighth ring-shaped groove  52   d  (hereinafter referred to as “first area”) and an area of opposition between the fourth ring-shaped groove  47   j  and the eighth ring-shaped groove  52   d  (hereinafter referred to as “second area”). In the state shown in  FIG. 5 , the first area and the second area are approximately the same, and therefore the flow amount is not determined by either of them. The flow amount of the working oil that is discharged from the retarding chambers  42  and flows through the retarding channels  44  is determined by the area of the fifth ring-shaped groove  47   k  and the tenth ring-shaped groove  52   i  (hereinafter referred to as “third area”). The flow amount of the working oil that is discharged from the first recessed portion  85  and the second recessed portion  86  and flows through the unlocking channels  45  is determined by the area of the second ring-shaped groove  47   h  and the ninth ring-shaped groove  52   h  (hereinafter referred to as “fourth area”). Hereinafter, description will be given under the assumption that the oil pressure of the working oil is constant, although this is not specifically stated. Accordingly, the flow amount of the working oil is determined by the size of the areas of opposition between the ring-shaped grooves. 
     If the amount of electricity supplied to the electromagnetic solenoid  54  is increased while the W1 state shown in  FIG. 3  is maintained, the spool  52  moves rightward from the state shown in  FIG. 5 . Accompanying the movement, the first area decreases monotonically and the second area increases monotonically. Accordingly, the flow amount is determined by the first area, and as shown in  FIG. 4 , the flow amount of the working oil that flows through the advancing channels  43  and is supplied to the advancing chambers  41  (solid line in the upper graph) decreases monotonically. The third area and the fourth area also decrease monotonically, and the flow amount of the working oil that is discharged from the retarding chambers  42  and flows through the retarding channels  44  (broken line in the upper graph) and the flow amount of the working oil that is discharged from the first recessed portion  85  and the second recessed portion  86  and flows through the unlocking channels  45  (broken line in the lower graph) also decreases monotonically. That is to say, when the amount of electricity supplied to the electromagnetic solenoid  54  is increased, the speed at which the relative rotation phase changes in the advance direction S 1  decreases. Paradoxically, the flow amounts of the working oil that flows through the advancing channels  43 , the retarding channels  44 , and the unlocking channels  45  in the lock transition mode (W1) increase monotonically as the position of the spool  52  approaches the left end due to the amount of electricity supplied to the electromagnetic solenoid  54  approaching 0, and are at their maximums when the electricity supply amount is 0. 
     If the flow amount of working oil that flows through the advancing channels  43  increases, the supply of working oil to the advancing chambers  41  is performed more rapidly, and if the flow amount of working oil that flows through the retarding channels  44  increases, the discharge of working oil from the retarding chambers  42  is performed more rapidly. If the supply and discharge of working oil to/from the advancing chambers  41  and the retarding chambers  42  is performed more rapidly, the speed at which the relative rotation phase changes in the advance direction S 1  increases. Also, if the flow amount of working oil that flows through the unlocking channels  45  is increased, the discharge of working oil in the first recessed portion  85  and the second recessed portion  86  is performed more rapidly. As a result, when the amount of electricity supplied to the electromagnetic solenoid  54  is 0, the speed at which the relative rotation phase changes in the advance direction S 1  reaches its maximum, and the working oil in the first recessed portion  85  and the second recessed portion  86  is discharged at the maximum speed. Accordingly, if the amount of electricity supplied to the electromagnetic solenoid  54  is set to 0 when the relative rotation phase is in the vicinity of the maximum retard phase, the state of being locked in the intermediate lock phase P can be realized in a short amount of time by changing the relative rotation phase in the advance direction S 1  at a high speed. 
     (2) W2 State 
     As shown in  FIG. 6 , if the amount of electricity supplied to the electromagnetic solenoid  54  is increased so that the OCV  51  enters the W2 state shown in  FIG. 3 , the spool  52  moves slightly rightward from the W1 state. If the working oil is supplied to the supply channel  47  in this state, the working oil will reach the seventh ring-shaped groove  52   c  and the eighth ring-shaped groove  52   d . The seventh ring-shaped groove  52   c  is connected to the unlocking channels  45  via the second ring-shaped groove  47   h , and therefore the working oil flows through the unlocking channels  45  so as to be supplied to the first recessed portion  85  and the second recessed portion  86 . In other words, the unlocking channels  45  are switched to the supply state. Accordingly, if the oil pressure of the supplied working oil exceeds the biasing force of the first spring  82  and the second spring  84 , the first lock member  81  and the second lock member  83  separate from the first recessed portion  85  and the second recessed portion  86  respectively, and the unlocked state is entered. Note that  FIG. 6  shows a state directly after a switch from the W1 state to the W2 state is performed. 
     The eighth ring-shaped groove  52   d  is still connected to the advancing channels  43 , and therefore the working oil flows through the advancing channels  43  and is supplied to the advancing chambers  41 . In other words, the advancing channels  43  are in the supply state. On the other hand, since the retarding channels  44  are still connected to the second through hole  52   f , the working oil in the retarding chambers  42  is discharged from the main discharge channel  52   b  to the outside of the valve opening/closing timing control device  10  through the third through holes  52   g . In other words, the retarding channels  44  are in the drain state. Accordingly, as shown in  FIG. 3 , the W2 state is a state in which working oil is supplied to the intermediate lock mechanism  8  (first recessed portion  85 , second recessed portion  86 ) and the advancing chambers  41  and the working oil is discharged from the retarding chambers  42  so that the relative rotation phase changes in the advance direction S 1 , and this corresponds to “an advancing action in an unlocked state”. The W2 state corresponds to a phase changeable mode in the present invention. 
     In the W2 state, the flow amount of the working oil that flows through the advancing channels  43  and is supplied to the advancing chambers  41  is determined by the first area, and the flow amount of the working oil that is discharged from the retarding chambers  42  and flows through the retarding channels  44  is determined by the third area. This is the same as the W1 state, but both the first area and the third area are even smaller than the smallest area in the W1 state. On the other hand, the flow amount of the working oil that flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86  is determined by the smaller of the area of opposition between the first ring-shaped groove  47   g  and the seventh ring-shaped groove  52   c  (hereinafter referred to as “fifth area”) and the area of opposition between the second ring-shaped groove  47   h  and the seventh ring-shaped groove  52   c  (hereinafter referred to as “sixth area”). In the state shown in  FIG. 6 , the sixth area is smaller than the fifth area, and therefore the flow amount is determined by the sixth area. 
     If electricity is further supplied to the electromagnetic solenoid  54  while the W2 state shown in  FIG. 3  is maintained, the spool  52  moves rightward from the state shown in  FIG. 6 . Accompanying the movement, the first area decreases monotonically. Accordingly, as shown in  FIG. 4 , the flow amount of the working oil that flows through the advancing channels  43  and is supplied to the advancing chambers  41  (the solid line in the upper graph) further decreases in comparison to the W1 state. The third area also decreases monotonically and the flow amount of the working oil that is discharged from the retarding chambers  42  and flows through the retarding channels  44  (the broken line in the upper graph) also further decreases in comparison to the W1 state. That is to say, when the amount of electricity supplied to the electromagnetic solenoid  54  is increased, the speed at which the relative rotation phase changes in the advance direction S 1  decreases further. 
     Although the fifth area decreases monotonically and the sixth area increases monotonically, the sixth area is still smaller, and therefore the flow amount of the working oil that flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86  (the solid line in the lower graph) is determined by the sixth area, and the flow amount increases. According to the above description, when the amount of electricity supplied to the electromagnetic solenoid  54  is the minimum for maintaining the W2 state, the flow amounts of the working oil that flows through the advancing channels  43  and the retarding channels  44  reach their maximum, and the flow amount of the working oil that flows through the unlocking channels  45  reaches its minimum. 
     As a result, as shown in  FIG. 4 , from the W1 state to the W2 state, the flow amount of the working oil that flows through the advancing channels  43  and is supplied to the advancing chambers  41 , and the flow amount of the working oil that is discharged from the retarding chambers  42  and flows through the retarding channels  44  both decrease monotonically, and the relative rotation phase changes in the advance direction S 1 . Also, the maximum flow amounts of the working oil that flows through the advancing channels  43  and is supplied to the advancing chambers  41  and the working oil that is discharged from the retarding chambers  42  and flows through the retarding channels  44  when in the lock transition mode (W1) are greater than the maximum flow amounts of the working oil that flows through the advancing channels  43  and is supplied to the advancing chambers  41  and the working oil that is discharged from the retarding chambers  42  and flows through the retarding channels  44  when in the phase changeable mode (W2). On the other hand, the working oil that flows through the unlocking channels  45  to be supplied to or discharged from the intermediate lock mechanism  8  is discharged as the flow amount decreases monotonically in the W1 state, and temporarily reaches 0 when switching from W1 to W2 is performed. Thereafter, upon switching to W2, switching from discharging to supplying is performed, and while in the W2 state, the flow amount of the working oil supplied to the intermediate lock mechanism  8  increases monotonically. 
     (3) W3 State 
     As shown in  FIG. 7 , if electricity is further supplied to the electromagnetic solenoid  54  so that the OCV  51  enters the W3 state shown in  FIG. 3 , the spool  52  moves slightly rightward from the W2 state. If the working oil is supplied to the supply channel  47  in this state, the working oil will reach the seventh ring-shaped groove  52   c  and the eighth ring-shaped groove  52   d . Since the seventh ring-shaped groove  52   c  is still connected to the unlocking channels  45 , the working oil flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86 . In other words, the unlocking channels  45  are in the supply state. Accordingly, in the W3 state as well, the unlocking state is maintained continuously from when in the W2 state. Note that  FIG. 7  shows a state near the center in the W3 state shown in  FIG. 3 . 
     The eighth ring-shaped groove  52   d  is not connected to any of the channels, and thus no more working oil flows thereto. In other words, the working oil is not supplied to the advancing channels  43  or the retarding channels  44 . Also, the advancing channels  43  and the retarding channels  44  are not connected to the first through hole  52   e  or the second through hole  52   f , and therefore a case does not occur in which the working oil in the advancing chambers  41  or the retarding chambers  42  is discharged to the outside of the valve opening/closing timing control device  10 . Accordingly, since supply and discharge of the working oil to/from the advancing chambers  41  and the retarding chambers  42  is not performed when the OCV  51  is controlled so as to be in the W3 state, the inner rotor  2  is held at the relative rotation phase at that time and does not change in the advance direction S 1  or the retard direction S 2 . Accordingly, as shown in  FIG. 3 , the W3 state is a state in which the working oil is supplied to the intermediate lock mechanism  8  (first recessed portion  85 , second recessed portion  86 ), the working oil is not supplied to or discharged from the advancing chambers  41  or the retarding chambers  42 , and the relative rotation phase is held. This corresponds to “intermediate phase holding”. The W3 state also corresponds to a phase changeable mode in the present invention. 
     In the W3 state, the flow amount of the working oil that flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86  is determined based on the magnitude relationship between the fifth area and the sixth area, but in  FIG. 7 , the fifth area and the sixth area are the same size. Accordingly, it is not determined by either of the areas. Also, if the electricity supply amount changes from this state so as to increase or decrease, a magnitude relationship will appear between the fifth area and the sixth area, and the flow amount will be determined by the smaller area. Accordingly, as indicated by the solid line in the lower graph in  FIG. 4 , when the spool  52  is at the position shown in  FIG. 7  (the center of the W3 state), the flow amount of the working oil that flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86  reaches its maximum, and the flow amount of the working oil decreases monotonically as the spool  52  moves left or right thereafter. 
     One significant problem that can occur when the intermediate lock mechanism  8  is in the unlocked state is that of entering the locked state due to at least one of the first lock member  81  and the second lock member  83  unintentionally being fit into the first recessed portion  85  and the second recessed portion  86 . When the locked state is entered, change in the relative rotation phase is restricted, and therefore there is a risk that it will not be possible to change to a desired relative rotation phase. In the state of being held at a relative rotation phase in which at least one of the first lock member  81  and the second lock member  83  is above the first recessed portion  85  or the second recessed portion  86 , an oil pressure pulsation is generated in the working oil accompanying variations in the torque of the camshaft  101  that occur due to the rotation of the cams  104 . An unintended locked state occurs when the lower limit value of the oil pressure pulsation falls below the oil pressure at which the unlocked state can be maintained. 
     In the present embodiment, as shown in  FIG. 4 , when in the W3 state, there is a position of the spool  52  at which the area (fifth area or sixth area) by which the passage of the working oil is determined reaches its maximum. Pressure loss accompanying passage of the working oil decreases as the area increases, and therefore if the area is at its maximum, the pressure loss in the working oil that flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86  is at its minimum. As a result, the lower limit value of the oil pressure pulsation can be increased, and the occurrence of an unintended locked state can be suppressed. 
     Also, regardless of which direction the spool  52  moves in from the position of the spool  52  at which the area reaches its maximum, the flow amount of the working oil that flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86  will decrease monotonically, and the flow amount for when switching between W2 and W1 is performed will be 0. Accordingly, it is possible to switch to the lock transition mode quickly and reliably. 
     (4) W4 State 
     As shown in  FIG. 8 , if electricity is further supplied to the electromagnetic solenoid  54  so that the OCV  51  enters the W4 state shown in  FIG. 3 , the spool  52  moves slightly rightward from the W3 state. If the working oil is supplied to the supply channel  47  in this state, the working oil will reach the seventh ring-shaped groove  52   c  and the eighth ring-shaped groove  52   d . Since the seventh ring-shaped groove  52   c  is still connected to the unlocking channels  45 , the working oil flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86 . In other words, the unlocking channels  45  are in the supply state. Accordingly, in the W4 state as well, the unlocked state is maintained continuously from when in the W2 and W3 states. Note that  FIG. 8  shows a state directly after a switch from the W3 state to the W4 state is performed. 
     In the W4 state, the eighth ring-shaped groove  52   d  is connected to the retarding channels  44  via the fifth ring-shaped groove  47   k , and therefore the working oil flows through the retarding channels  44  and is supplied to the retarding chambers  42 . In other words, the retarding channels  44  are in the supply state. On the other hand, the advancing channels  43  are connected to the first through hole  52   e  via the third ring-shaped groove  47   i  and the ninth ring-shaped groove  52   h , and therefore the working oil in the advancing chambers  41  flows from the main discharge channel  52   b  and is discharged to the outside of the valve opening/closing timing control device  10  through the third through holes  52   g . In other words, the advancing channels  43  are in the drain state. Thus, as shown in  FIG. 3 , the W4 state is a state in which the working oil is supplied to the intermediate lock mechanism  8  (first recessed portion  85 , second recessed portion  86 ) and the retarding chambers  42 , the working oil is discharged from the advancing chambers  41 , and the relative rotation phase changes in the retard direction S 2 . This corresponds to “a retarding action in an unlocked state”. The W4 state also corresponds to a phase changeable mode in the present invention. 
     In the W4 state, the flow amount of the working oil that is discharged from the advancing chambers  41  and flows through the advancing channels  43  is determined by the opposing areas of the third ring-shaped groove  47   i  and the ninth ring-shaped groove  52   h  (hereinafter referred to as “seventh area”). The flow amount of the working oil that flows through the retarding channels  44  and is supplied to the retarding chambers  42  is determined by the smaller of the second area and the area of opposition between the eighth ring-shaped groove  52   d  and the fifth ring-shaped groove  47   k  (hereinafter referred to as “eighth area”). In the state shown in  FIG. 8 , the eighth area is smaller than the second area, and therefore the flow amount of the working oil is determined by the eighth area. The flow amount of the working oil that flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86  is determined by the fifth area since the fifth area is smaller than the sixth area. 
     If electricity is further supplied to the electromagnetic solenoid  54  while the W4 state shown in  FIG. 3  is maintained, the spool  52  moves rightward from the state shown in  FIG. 8 . Accompanying the movement, the seventh area increases monotonically. Accordingly, as shown in  FIG. 4 , the flow amount of the working oil that is discharged from the advancing chambers  41  and flows through the advancing channels  43  (the broken line in the upper graph) increases from the W3 state. Although the second area does not change, the eighth area increases monotonically, and the flow amount of the working oil that flows through the retarding channels  44  and is supplied to the retarding chambers  42  (solid line in the upper graph) also increases from the W3 state. That is to say, when the amount of electricity supplied to the electromagnetic solenoid  54  is increased, the speed at which the relative rotation phase changes in the retard direction S 2  increases. 
     Since the fifth area decreases monotonically and the sixth area increases monotonically, the flow amount of the working oil that flows through the unlocking channels  45  and is supplied to the first recessed portion  85  and the second recessed portion  86  (the solid line in the lower graph) decreases. That is to say, when the amount of electricity supplied to the electromagnetic solenoid  54  is the minimum for maintaining the W4 state, the flow amounts of the working oil that flows through the advancing channels  43  and the retarding channels  44  reach their minimums, and the flow amount of the working oil that flows through the unlocking channels  45  reaches its maximum. 
     As shown in  FIG. 9 , if the amount of electricity supplied to the electromagnetic solenoid  54  is increased to its maximum so that the OCV  51  enters the state of being on the right end of W4 shown in  FIG. 3 , the spool  52  moves slightly rightward from the state shown in  FIG. 8 , comes into contact with the bottom surface of the accommodation space  5   a , and stops. This state corresponds to the W4E state shown in  FIG. 4 . At this time, the seventh area reaches its maximum, and therefore the flow amount of the working oil that is discharged from the advancing chambers  41  and flows through the advancing channels  43  reaches its maximum. Also, since the eighth area is also at its maximum, the flow amount of the working oil that flows through the retarding channels  44  and is supplied to the retarding chambers  42  also reaches its maximum. That is to say, the speed at which the relative rotation phase changes in the retard direction S 2  reaches its maximum. On the other hand, since the fifth area reaches 0, the working oil does not flow through the unlocking channels  45  and the working oil is not supplied to the first recessed portion  85  and the second recessed portion  86 . At this time, although the sixth area is at its maximum, the unlocking channels  45  are only connected to the seventh ring-shaped groove  52   c , and therefore the working oil in the first recessed portion  85  and the second recessed portion  86  does not flow through the unlocking channels  45  and is not discharged. 
     In the lock transition mode of the valve opening/closing timing control device  10  according to the present embodiment with the above-described configuration, there is a positive correlative relationship between the flow amount of the working oil that flows through the advancing channels  43 , the flow amount of the working oil that flows through the retarding channels  44 , and the flow amount of the working oil that flows through the unlocking channels  45 . Specifically, when the amount of electricity supplied to the electromagnetic solenoid  54  approaches 0, the flow amount of the working oil that flows through the advancing channels  43 , the flow amount of the working oil that flows through the retarding channels  44 , and the flow amount of the working oil that flows through the unlocking channels  45  all increase. If the flow amount of the working oil that flows through the advancing channels  43  increases, the supply of working oil to the advancing chambers  41  is performed more rapidly, and if the flow amount of working oil that flows through the retarding channels  44  is increased, the discharge of working oil from the retarding chambers  42  is performed more rapidly. If the supply of working oil to the advancing chambers  41  and the retarding chambers  42  is performed more rapidly, the speed at which the relative rotation phase changes in the advance direction S 1  increases. Also, if the flow amount of the working oil that flows through the unlocking channels  45  increases, the discharge of working oil in the first recessed portion  85  and the second recessed portion  86  is performed more rapidly. 
     Accordingly, when the amount of electricity supplied to the electromagnetic solenoid  54  is 0, the flow amount of the working oil that flows through the advancing channels  43 , the flow amount of the working oil that flows through the retarding channels  44 , and the flow amount of the working oil that flows through the unlocking channels  45  all reach their maximums. Therefore, the speed at which the relative rotation phase changes in the advance direction S 1  can be maximally increased, and the working oil in the first recessed portion  85  and the second recessed portion  86  can be discharged at the maximum speed. Accordingly, by setting the amount of electricity supplied to the electromagnetic solenoid  54  to 0 when the relative rotation phase is in the vicinity of the maximum retard phase, the relative rotation phase can be changed in the advance direction S 1  at a high speed and the state of being locked in the intermediate lock phase P can be realized in a short amount of time. 
     Also, in the phase changeable mode of the valve opening/closing timing control device  10  according to the present embodiment, when in a state where the relative rotation phase is held (W3 state), the area that determines the passage of the working oil to the intermediate lock mechanism  8  reaches its maximum. Pressure loss accompanying passage of the working oil decreases as the area increases, and therefore if the area is at its maximum, the pressure loss in the working oil that is supplied to the intermediate lock mechanism  8  is at its minimum. As a result, the lower limit value of the oil pressure pulsation of the working oil can be raised, and the occurrence of an unintended locked state can be suppressed. 
     Also, the valve opening/closing timing control device  10  according to the present embodiment is configured such that regardless of the direction in which the spool  52  moves from the position of the spool  52  at which the area is at its maximum, the flow amount of the working oil that is supplied to the intermediate lock mechanism  8  decreases monotonically and becomes 0 when switching between W2 and W1 is performed. Accordingly, it is possible to switch from the phase changeable mode to the lock transition mode quickly and reliably. 
     2. Second Embodiment 
     Hereinafter, the valve opening/closing timing control device  10  according to a second embodiment of the present invention will be described in detail with reference to the drawings. In the description of the present embodiment, portions of the configuration that are the same as in the first embodiment are denoted by the same reference numerals, and description relating to similar configurations will not be repeated here. In the valve opening/closing timing control device  10  of the present embodiment, lock discharge channels  46  are formed in addition to the unlocking channels  45  as channels through which the working oil that is supplied to and discharged from the intermediate lock mechanism  8  flows. 
     Similarly to the unlocking channels  45 , the lock discharge channels  46  are also connected to the bottom surfaces of the deep groove of the first recessed portion  85  and the deep groove of the second recessed portion  86 . However, the unlocking channels  45  allow the passage of working oil that is supplied to and discharged from the first recessed portion  85  and the second recessed portion  86 , whereas the lock discharge channels  46  do not allow passage of the working oil supplied to the first recessed portion  85  and the second recessed portion  86  and allow only passage of the working oil that is discharged from the first recessed portion  85  and the second recessed portion  86  to the outside of the valve opening/closing timing control device  10 . 
     As shown in  FIGS. 10, 11 , and  FIGS. 14 to 19 , the lock discharge channels  46  that connect to the first recessed portion  85  and the second recessed portion  86  are each constituted by a first discharge portion  46   a  formed in a fixing bolt  5 , and a second discharge portion  46   b  that is connected to the first discharge portion  46   a  and is formed in the inner rotor  2 . The first discharge portion  46   a  is connected to a sixth ring-shaped groove  47   m  formed in the inner circumferential surface opposing the accommodation space  5   a  of the fixing bolt  5 . 
     Operation of OCV 
     (1) W1 State 
     As shown in  FIG. 14 , if no electricity is supplied to the electromagnetic solenoid  54  (the electricity supply amount is 0), the OCV  51  is in the W1 state shown in  FIG. 12 , and due to the biasing force of the first valve spring  53   a , the spool  52  comes into contact with the stopper  55  and is located leftmost. When working oil is supplied to the supply channel  47  in this state, similarly to the first embodiment, the working oil that flows through the advancing channels  43  is supplied to the advancing chambers  41 , and at the same time, the working oil is discharged from the retarding chambers  42  and flows through the retarding channels  44  and the working oil discharged from the intermediate lock mechanism  8  also flows through the unlocking channels  45 . At this time, the working oil that flows through the lock discharge channels  46  is discharged to the accommodation space  5   a  via the sixth ring-shaped groove  47   m , and thereafter is discharged from the main discharge channel  52   b  to the outside of the valve opening/closing timing control device  10  through the third through holes  52   g . That is to say, the working oil in the intermediate lock mechanism  8  (first recessed portion  85 , second recessed portion  86 ) is discharged from both the unlocking channels  45  and the lock discharge channels  46 . Hereinafter, the unlocking channels  45 , the second ring-shaped groove  47   h , the ninth ring-shaped groove  52   h , the first through hole  52   e , the lock discharge channels  46 , and the sixth ring-shaped groove  47   m  in the W1 state of the present embodiment will be collectively referred to as a first discharge channel. 
     As shown in  FIG. 12 , the W1 state is a state in which working oil is discharged from intermediate lock mechanism  8  (first recessed portion  85  and second recessed portion  86 ) and the retarding chambers  42 , the working oil is supplied to the advancing chambers  41 , and thereby the relative rotation phase changes in the advance direction S 1 . This corresponds to “locking in an intermediate lock phase P by means of an advancing action”. The W1 state corresponds to a lock transition mode in the present invention. 
     In the W1 state, the flow amount of the working oil that is discharged from the first recessed portion  85  and the second recessed portion  86  and flows through the unlocking channels  45  is determined by a fourth area, which is the same as that in the first embodiment, and the flow amount of the working oil that is discharged from the first recessed portion  85  and the second recessed portion  86  and flows through the lock discharge channels  46  is determined by the area of opposition between the sixth ring-shaped groove  47   m  and the accommodation space  5   a  (hereinafter referred to as “ninth area”). Accordingly, the flow amount of the working oil that flows through the first discharge channel so as to be discharged is determined by the sum of the fourth area and the ninth area. 
     As shown in  FIG. 13 , when in the W1 state, the relationship between the amount of electricity supplied to the electromagnetic solenoid  54  and the flow amount of the working oil that flows through the advancing channels  43 , the retarding channels  44 , and the first discharge channel is the same as in the first embodiment. That is to say, when the amount of electricity supplied to the electromagnetic solenoid  54  is 0, all of the flow amounts reach their maximum, the speed at which the relative rotation phase changes in the advance direction S 1  reaches its maximum, and the working oil in the first recessed portion  85  and the second recessed portion  86  is discharged at the maximum speed. Also, as the electricity supply amount increases, the flow amount decreases, and the speed at which the relative rotation phase changes in the advance direction S 1  also decreases. 
     (2) W2, W3, and W4 States 
     As shown in  FIGS. 12, 15, 16, and 17 , when the OCV  51  is in the W2, W3, and W4 states, the lock discharge channels  46  are not connected to the supply channel  47  or the main discharge channel  52   b , and therefore no working oil flows through the lock discharge channels  46 . That is to say, the increasing/decreasing tendencies of the working oil that flows through the advancing channels  43 , the retarding channels  44 , and the unlocking channels  45  in the W2, W3, and W4 states are the same as in the first embodiment, as shown in  FIGS. 12 and 13 . That is to say, the W2 state corresponds to “an advancing action in an unlocked state”, the W3 state corresponds to “intermediate phase holding”, and the W4 state corresponds to “a retarding action in an unlocked state”, and all of these states correspond to the phase changeable mode. For this reason, in the present embodiment, detailed description thereof is not included. 
     (3) W5 State 
     In the present embodiment, even if the state shown in  FIG. 9  in the first embodiment (W4E state) is entered, there is a gap between the spool  52  of the OCV  51  and the bottom surface of the accommodation space  5   a , and by increasing the amount of electricity supplied to the electromagnetic solenoid  54 , the spool  52  moves further rightward, entering the W5 state shown in  FIG. 18 . When the working oil is supplied to the supply channel  47  in this state, the working oil discharged from the advancing chambers  41  flows through the advancing channels  43  continuously from when in the W4 state, and the working oil that flows through the retarding channels  44  is supplied to the retarding chambers  42 . Although the working oil that flows through the unlocking channels  45  is connected to the seventh ring-shaped groove  52   c , the seventh ring-shaped groove  52   c  and the first ring-shaped groove  47   g  do not oppose each other, and the fifth area is 0. In other words, no working oil flows through the unlocking channels  45 . 
     When in the W5 state, the working oil in the intermediate lock mechanism  8  flows through only the lock discharge channels  46 , is discharged from the second through hole  52   f  to the main discharge channel  52   b  via the sixth ring-shaped groove  47   m  and the tenth ring-shaped groove  52   i , and is discharged to the outside of the valve opening/closing timing control device  10  through the third through holes  52   g . Hereinafter, the lock discharge channels  46 , the sixth ring-shaped groove  47   m , the tenth ring-shaped groove  52   i , and the second through hole  52   f  in the W5 state of the present embodiment will be referred to collectively as a second discharge channel. 
     As shown in  FIG. 12 , the W5 state is a state in which the working oil is discharged from the intermediate lock mechanism  8  (first recessed portion  85  and second recessed portion  86 ) and the advancing chambers  41 , the working oil is supplied to the retarding chambers  42 , and thereby the relative rotation phase changes in the retard direction S 2 . This corresponds to “locking in an intermediate lock phase P by means of a retarding action”. The W5 state also corresponds to a lock transition mode of the present invention, similarly to the W1 state. 
     In the W5 state, the flow amount of the working oil that is discharged from the advancing chambers  41  and flows through the advancing channels  43  is determined by the seventh area, and the flow amount of the working oil that flows through the retarding channels  44  and is supplied to the retarding chambers  42  is determined by the eighth area. This is the same as the W4 state, but both the seventh area and the eighth area are even larger than the maximum area in the W4 state. On the other hand, the flow amount of the working oil that flows through the second discharge channel so as to be discharged is determined by the area of opposition between the sixth ring-shaped groove  47   m  and the tenth ring-shaped groove  52   i  (hereinafter referred to as “tenth area”). 
     If electricity is further supplied to the electromagnetic solenoid  54  while the W5 state shown in  FIG. 18  is maintained, the spool  52  moves rightward from the state shown in  FIG. 18 , and as shown in  FIG. 19 , the spool  52  comes into contact with the bottom surface of the accommodation space  5   a  and stops. As shown in  FIGS. 18 and 19 , the seventh area increases monotonically as the spool  52  moves rightward. Accordingly, as shown in  FIG. 13 , the flow amount of the working oil that is discharged from the advancing chambers  41  and flows through the advancing channels  43  (broken line in the upper graph) continues to increase as in the W4 state. In the retarding channels  44 , the second area decreases slightly, but since the eighth area, which is even smaller, increases monotonically, the eighth area is the determinant. For this reason, the flow amount of the working oil that flows through the retarding channels  44  and is supplied to the retarding chambers  42  (solid line in the upper graph) also continues to increase as in the W4 state. That is to say, when the amount of electricity supplied to the electromagnetic solenoid  54  is increased, the speed at which the relative rotation phase changes in the retard direction S 2  increases further. 
     Since the tenth area increases monotonically, the flow amount of the working oil that is discharged from the first recessed portion  85  and the second recessed portion  86  and flows through the second discharge channel (broken line in the lower graph) increases. That is to say, when the amount of electricity supplied to the electromagnetic solenoid  54  is the minimum for maintaining the W5 state, the flow amounts of the working oil that flows through the advancing channels  43 , the retarding channels  44 , and the second discharge channel reach their minimum, and as the electricity supply amount increases, the flow amounts also increase. 
     As a result, as shown in  FIG. 13 , from the W4 state to the W5 state, the flow amount of the working oil that is discharged from the advancing chambers  41  and flows through the advancing channels  43  and the flow amount of the working oil that flows through the retarding channels  44  and is supplied to the retarding chambers  42  both increase monotonically, and the relative rotation phase changes in the retard direction S 2 . Also, the maximum flow amounts of the working oil that is discharged from the advancing chambers  41  and flows through the advancing channels  43  and the working oil that flows through the retarding channels  44  and is supplied to the retarding chambers  42  when in the lock transition mode (W5) are larger than the maximum flow amounts of the working oil that is discharged from the advancing chambers  41  and flows through the advancing channels  43  and the working oil that flows through the retarding channels  44  and is supplied to the retarding chambers  42  when in the phase changeable mode (W4). On the other hand, the working oil that flows through the lock discharge channels  46  and is supplied to or discharged from the intermediate lock mechanism  8  is discharged as the flow amount decreases monotonically in the W4 state, and temporarily reaches 0 when switching from W4 to W5 is performed. Thereafter, upon switching to W5, switching from supplying to discharging is performed, and while in the W5 state, the flow amount of the working oil discharged from the intermediate lock mechanism  8  increases monotonically. 
     As shown in  FIG. 13 , the absolute value of the slope of the change in the flow amount of the working oil that flows through the second discharge channel when the electricity supply amount of the electromagnetic solenoid  54  in the W5 state is changed is greater than the absolute value of the slope of the change in the flow amount of the working oil that flows through the first discharge channel when the electricity supply amount of the electromagnetic solenoid  54  in the W1 state is changed. This is because the tenth area in the W5 state is configured to be greater than the sum of the fourth area and the ninth area in the W1 state. 
     In the present embodiment, similarly to the first embodiment, an average displacement force caused by variations in the torque of the camshaft  101  that are generated by the rotation of the cams  104  acts on the inner rotor  2 , and the direction in which it acts is the retard direction S 2 . Also, the biasing force in the advance direction S 1  of the return spring  70  acts from the maximum retard phase to the intermediate lock phase P, but it is canceled out by the average displacement force in the retard direction S 2 . As a result, the speed with which the relative rotation phase is changed toward the retard side when in the vicinity of the maximum advance phase (retard change speed) is greater than the speed with which the relative rotation phase is changed toward the advance side when in the vicinity of the maximum retard phase (advance change speed). For this reason, in order to rotate the inner rotor  2  in the retard direction S 2  so as to reliably constrain the relative rotation phase to the intermediate lock phase P, the speed at which the working oil is discharged from the first recessed portion  85  and the second recessed portion  86  needs to be made greater than when the inner rotor  2  is rotated in the advance direction S 1  so as to constrain the relative rotation phase to the intermediate lock phase P. 
     In the present embodiment, the ratio of the tenth area to the sum of the fourth area and the ninth area, or in other words, the ratio of the flow amount of the working oil that flows through the second discharge channel to the flow amount of the working oil that flows through the first discharge channel is increased to be greater than or equal to the ratio of the retard change speed to the advance change speed. With this configuration, the speed at which the working oil is discharged from the first recessed portion  85  and the second recessed portion  86  can be increased, and even when the inner rotor  2  is rotated in the retard direction S 2 , the relative rotation phase can be reliably constrained to the intermediate lock phase P. 
     3. Other Embodiments 
     In the first embodiment and the second embodiment, the supply and discharge of the working oil to/from the advancing chambers  41 , the retarding chambers  42 , and the intermediate lock mechanism  8  is controlled by one OCV  51  arranged inside of the inner rotor  2 , but there is no limitation to this. For example, a configuration may be used in which the functions of the OCV  51  are divided into two, an OCV  51 A that controls only the supply and discharge of the working oil to/from the advancing chambers  41  and the retarding chambers  42  is arranged on the inside of the inner rotor  2 , and an OCV  51 B that controls the supply and discharge of working oil to/from the intermediate lock mechanism  8  is arranged on the outside of the housing  1 . Also, as shown in  FIG. 20 , a configuration may be used in which both the OCV  51 A and the OCV  51 B are arranged on the outside of the housing  1 . In such a case, it is preferable to use a three-position proportional control valve in which the flow amount of the working oil changes due to the position of the spool  52  as the OCV  51 A. 
     With this kind of configuration as well, it is possible to obtain effects similar to those obtained in the first embodiment and the second embodiment. 
     INDUSTRIAL APPLICABILITY 
     The present invention can be used in a valve opening/closing timing control device that controls a relative rotation phase of a driven rotating body with respect to a driving rotating body that rotates synchronously with a crankshaft of an internal combustion engine. 
     DESCRIPTION OF REFERENCE SIGNS 
     
         
         
           
               1  Housing (driving rotating body) 
               2  Inner rotor (driven rotating body) 
               4  Fluid pressure chamber 
               8  Intermediate lock mechanism 
               10  Valve opening/closing timing control device 
               21  Protruding portion (partition) 
               41  Advancing chamber 
               42  Retarding chamber 
               43  Advancing channel 
               44  Retarding channel 
               51  OCV (electromagnetic valve) 
               52  Spool 
               101  Camshaft 
             C Crankshaft (driving shaft) 
             E Engine (internal combustion engine) 
             P Intermediate lock phase 
             S 1  Advance direction 
             S 2  Retard direction 
             X Axis